It will depend on condition. A lot of police agencies use reloaded ammunition for practice, since it's cheaper and they have to make their budgets go as far as they can.
The current scrap price for yellow brass in my area is $1.95 a pound. Count in your time for sorting it and add what you think is fair to the scrap price and that will give you an idea of what to expect. The price you get will depend a lot on the caliber and condition of the brass, and the demand for what you have in your area. A dealer isn't going to give you much, since he has to make a profit on it when he sells it, plus the time value of money while he has it in his inventory.
I've been selling it sorted by caliber for $3.50 a pound, plus shipping. I don't worry very much about the caliber, since I buy it by the pound from the Rod & Gun Club, but it's all mixed together when I get it, and about 30% is .22 rimfire, with some steel and aluminum mixed in, along with some sand.
Don't expect to get rich off your find. You'll discover that the time involved sometimes just isn't worth it.
I've got 5 five gallon buckets of .40 S&W brass in the garage right now that I'm trying to peddle. It might just go to the scrap dealer, just because I need the room.
Hope this helps.
Fred