What kind of stuff? Gear or clothing?
Gear: it depends on what you need. Tactical Tailor is cheap and good for the standard mag pouches, backpacks, etc. I like Paraclete, Mayflower, and Blueforce Gear but they're more spendy and specialized. Check out
www.greygrouptraining.com, they sell all of the above.
Clothing: Propper or Tru Spec can be had for about $60-70 a set. Crye is where it's at, but you can get 3 full sets of the above for what one set of Crye Combat pants runs.