US Army Garrison Schinnen is a small facility that supports a relatively small number of people in the Germany/BENELUX area. With that in mind though I think you will find that USAG Schinnen can meet most of your shopping needs. On this small camp is a PX, Shopette w/bookstore, Class 6 Store, PX-tra, Commissary, and a couple concessions.
PX
The PX is not real big but it has most of what you need. If they don't have it on hand it can be special ordered. The PX has two floors. The PX is closed on Mondays and most US holidays.
The bottom floor is the high tech section of the store (Power Zone). Here you can shop for computers, TVs, DvDs, digital cameras, GPSs, and all sorts of parts for connecting and using your electronic gear. The TV selection is pretty good with a good assortment of flat screen TVs. Not all of them are multi-system though so if you are going to connect to the Dutch or German TV cables systems you need to make sure you get a multi-system TV. Off and on they sell AFN satellite dishes and peripherals. They also have a pretty good selection of computer games and console type games (Wii, Xbox, etc.) but they don't carry a lot of any particular game.There sometimes are concession sales (leather coats, wines, clocks, etc.) in the lower floor hallway. The registers are all centrally located in the Power Zone.
Upstairs is the clothing and shoe store. There is not a huge selection at any given time but it seems that they rotate the clothes pretty well. Truthfully, I don't go up there all that often, I have all the clothes that I need, but whenever I do go there it appears like there is new stuff there. They have a very good sales rack and I do make a point to check that out when I am there. The shoe selection is very small. I've never bought shoes here so I don't know how well stocked the back room is for sizes. They recently moved the Military Clothing Sales from the main clothing room to its own room. When they did this they also expanded what they carried. For the size of the PX this is a pretty good clothing sales store. I used to drive to Belgium to get military clothing items but won't have to anymore. There is a small gifts concession upstairs, where it used to be 12 years ago. It is mostly Dutch touristy type stuff, fine if you need a gift for someone back in the states. It is priced in Euros so figure out the dollar value before you think it's a good deal. There is also a multi-purpose room now with limited selections of perfume, over the counter meds, candles (Yankee Candle), and curios. There is usually seasonal stuff on sale in the hallway at the top of the stairs (there is an elevator for those who would need it). Finally the customer service window is at the back end of the upstairs. Here you can cash checks, buy postage stamps, exchange currency (slightly more expensive rate than at the bank), return or exchange purchased items, etc.
Shoppette
The Shoppette was just reconfigured because they are moving the concession stores from outside the building to the former Book Store area. This required them to move the Book Store into the Shoppette. That's a shame because the former Book Store was set up real nice like a stateside book store with a coffee bar. So now the Shoppette has the book store, very limited food items, the Class 6 store, cards and stationary, and DvD rentals. The Shoppette just recently added Monday hours, which is really nice. The Shoppette is right next to the PX.
Food Court
Just down from the Shoppette is the food court, sort of. Basically it is a small Burger King, Anthony's Pizza, and Baskin Robbins shop. There is often only two workers there (one is the cook) so don't expect extremely fast service. The ice cream is ridiculously expensive; you can get better ice cream out on the economy for 2/3s the price. Burger King is everywhere the Army is and this one gets just enough business to stay open, which means the food is surprisingly fresh. After 33 years in the Army it is a rare day that you'll see me in a Burger King but maybe once every two or three months I eat there.
Concessions
Right now they are still outside but they should be moving into the former Book Mart sometime soon. These include New Car Sales, Car Rental (the car rental guy is the friendliest man in the world I think), flower shop, Barber, and beauty salon. I've rented cars there but otherwise I have not used these services. My son was never happy with the barber shop.
PX-TRA
Down the road a bit is the newly redone PX-TRA. They moved all the household goods (small appliances, pillows, sheets, kitchenware, etc.) down here. As a result of the loss of space in the store their outdoors, tools, and gardening shelf space has been cut in half or less. There is a very small selection of sports/fitness supplements, gloves, and stuff like that. There is a small bike shop with the standard low-end bike brands and bike equipment (plenty good enough for the kids though). There is a pet section (redundant with the commissary), outdoor/camping section, small selection of tools, and kids toys. Toys takes over most of the shelf space during the fall and Christmas season.
Commissary
The commissary is nothing to complain about. It is bigger than the population probably warrants. Selection is limited to a few brands but I think you will be able to find everything you need. Schinnen is at the far end of the supply line so shelves are often empty and items are often approaching their "Sell By" date. The commissary, like all the other stores on the camp except the Shoppette, is closed on Mondays. Shelves are often low on Sundays. So try to stock up on needed items before the weekend if at all possible. I have special ordered a few items and they generally are happy to get them for you if they exist in the commissary warehouse. Remember the commissary tax. There is a five percent "surcharge" (just a tax by another name) so you can sometimes by the same items at one of the other stores cheaper. A good example is the Stars & Stripes newspaper. The Sunday edition is $1.00 at the PX or Shoppette but $1.05 (because of the tax) at the commissary. That five percent will add up over time. Breads are, I think, shipped in from the states so they are never fresh. Buy bread downtown at your local C1000, Aldi, or Jumbo store (it's better, fresher, and cheaper). The meats aren't great either, it also comes frozen from the states, but you'll rarely be able to buy meats cheaper on the economy. The fruit and vegetable section is usually pretty bad. They mishandle the goods and they are usually bruised and prone to early spoilage. This is something else you should probably buy on the economy. Milk is much cheaper here than on the economy even though the Dutch produce a lot of milk and other dairy products. Canned goods and dry goods are a good deal here and these are usually stocked pretty well.
Aafes Gas Station
Well they pretty much have a monopoly so you're going to buy your fuel, lubricants, and car care items here. They are quite a bit more expensive than a stateside store but probably close to half what you would pay on the economy. Get a Star Card and you can save five cents a gallon on your fuel. That might not seem like much but it will add up big time over the course of you time here.
I believe that is it. With some experience and asking around you will quickly figure out what to buy at Schinnen and what to buy on the economy. I probably buy close to 35-40% of my groceries on the economy, partly because I live across the street from a C1000 store. I try to walk through an Aldi store at least once a month because their sale items can't be beat by anyone, especially household paper products (paper towels, toilet tissue, etc.). I much prefer the Dutch bread, fruits and vegetables, and desserts and ice cream over what is available in the commissary. But price dictates other items like milk and meat will be purchased at the commissary. Every once in a while I pick up some meat on the economy because of a sale, the much higher quality, or just for something different. This includes things like shawarma meat, rotisserie chickens, gyros meat, etc.