Do any vets on the board take advantage of PX privileges that were opened up a year or two ago ?
There are two different aspects to shopping at the PX/Exchange on a military base.
The PX sells the "department store" type of stuff. By law, it must at least break even and be self-sufficient. In my experience (37 years of combined active duty and retired use) the prices are usually a bit cheaper at the PX than out in town, but not always. You need to shop around. When shopping on base you do not pay sales tax, so this is a savings. The profits contribute funding to base recreation services, so this may be worth considering as well.
The commissary is the base grocery store. By law, the commissary is subsidized by the military budget, and commissary prices are often a lot cheaper than in the local grocery stores. My wife and I do a price comparison between the commissary and the local grocery stores every year or two, and the commissary is always cheaper on most items. Sometimes a lot cheaper. The percentage of savings can vary widely from product to product.
We currently live about 45 minutes from the nearest base and usually drive to the base about once every 4 - 6 weeks to stock up. We usually spend between $250 and $350 at the commissary when we make the trip. We estimate we save between $100 and $150 compared to the local grocery stores. The savings will vary depending on what you buy. For us, it is substantial and worth the occasional trip.
If you are eligible, I'd recommend comparing prices for a basket of goods that you usually use and see for yourself whether the PX/commissary are worth it for you.
Hint: If you need something that is sold by both the commissary and the PX, it will be cheaper at the commissary due to the subsidies.