Maybe as a side-business, but don't quit your day job. As has been mentioned, most places already have arrangements in place. Storage is expensive. It is also time consuming to sort through multiple calibers, let alone multiple headstamps. Look at what
www.brassmanbrass.com and
www.midwayusa.com charge for used brass as well as Ebay. I recently paid about $70 for 3000 9mm cases off Ebay. It was clean but not deprimed.
Here's what you do: keep a 5 gallon bucket in your car and put any and all brass you find at the range in it. Once it's full, sort it by caliber, separating any non-reloadable cases (steel, aluminum, berdan-primed). Count it too, then see how long it took you. Depriming is optional, but certainly a good value-added service. Now, load it into a tumbler and clean each batch. You'll have to pay for tumblers and polishing media. Don't forget the cost of electricity to run the tumblers. Be sure to account for the wear and tear on a tumbler, they won't last forever, especially cleaning hundreds of rounds a day. Now, bag it and box it, then check the postal rates. Before you set a price, be sure to check current market prices by looking at your competitors on ebay, brassman, and midway. Pony up a few more bucks for ebay listing costs, paypal fees, time & gas to the post office, and packing material. If you have a website, you'll need to pay for site design, hosting, maintenance, and merchant fees for credit cards. You've been keeping track of every hour and nickel spent on this so far, right?
You'll also have to pay your accountant a little extra to fill out a Schedule C, 1065, or 1120S every year. It's also illegal to run a business out of your home in certain areas without the proper licenses or permits. Pony up a few more $$$ for those permits.
Oh yeah, and your wife will be pissed because there's dirty, smelly, toxic brass all over the house. Your kids will forget your name and your fingers will turn black. You'll also gaze at your bank statement wondering WHY you aren't making money at this!
Still wanna sell brass? (And this was all for a dinky brass selling operation! Next time you meet a successful small business owner, pat them on the back.)
My advice: scrounge what you can, even calibers you don't shoot. Once you have gallon bags full of a caliber, then sell them on ebay or give them to friends. Trade with other THR members. Don't bother with making it a business.