Free: Contests & Raffles.
If your looking for factory ammunition. Double Tap, Winchester & Nosler all have factory 7mm Magnum offerings with the 160gr Nosler Accubond. Which is a excellent bullet with a great BC.
Do you handload? If so, I'd look into Bergers. They're like mini-grenades you can fire from a rifle. If not, I'd suggest some sort of factory load with Barnes bullets.