Free: Contests & Raffles.
I use a 6.5x20x50 Vortex Viper and I love it. The thing you will see is every one has a different opinion. I know some guys are all about FOV for coyotes some like big glass. I think a middle ground scope is the best. The most important thing is to get a scope on the gun and practice different angles and situations and get good with what you have.