I just started trap shooting and i love it. My question is what should i be doing with my empty hulls? Should i keep them and sell/give them to the guys at the range? What shells are most reloadable? Right now i have 200 empty rem low brass sport hulls, are they worth anything?

The hulls you mentioned are pretty much worthless.

If you really like trap, be warned, it is very addictive and destructive to your bank account.

Most serious trap shooters, once fully hooked, shoot at least a 1000 shells a week, not to mention guns, stocks, target costs, etc.

Unless you are quite wealthy, you will wind up reloading. Until then, shoot the most popular target load hull in your area, save them and sell them to other shooters and you will be shooting much better shells for about the same cost as the promo loads that you are shooting now. Or, save them for the inevitable time when you decide that you have to reload to save money, so you can shoot more, and spend more. That makes perfect sense, I think.