Free: Contests & Raffles.
What caliber? What ranges you looking at shooting? Starline makes great brass. If you not shooting 1000 yards and pushing your brass to the max, starline would be my choice.
Lapua makes the best brass, but it's up to you if you want to spend the money on it. I do feel quality brass is a good investment. Although I have never bought Lapua brass myself. But I think it would be a good idea to start out with the best.
Agree with Karl, But I will throw ADG, and Alpha. Lapua has always been the bench mark for brass. It depends on what kind of accuracy you are after. The amount of reloads depend on how hot you run them. If you can't shoot small groups, or don't have the reloading experience/time to dial the rifle in, you won't know the difference. My brother in law is a brass rat. Picks up anything on the ground to reload at the range. Me, I won't even mix lots of Lapua for the same caliber. It really depends on what you are expecting the rifle to shoot accuracy wise.