Re: Newbie here - howdy!
For scopes in this price range, consider the Nikon Tactical, IOR, Super Sniper and Xotic. The super sniper has very useable optics and priced right. They work very well but a fixed mag.
If you want a LR varmint rifle, the 308 will limit you a lot once you go past 500yds. Wind drift is just too high for pop can size targets.
Consider the 6mm and 6.5's that are used in 1000yd BR shooting. They are shooting these for a reason. No shortage of info in old posts or at BRCentral.com.
For factory rds, consider the 243, 260Rem, 7-08. For wildcats, 6BR and stretched versions, 6.5 Mystic and 6.5-243 AI versions, 6.5 -284.
I have shot and owned many 308's so have lots of experience with this rd. There is simply no comparison in wind drift when compared to these other cals.
If you don't mind the 308 ballistics, then consider a fast twist 223 and launch 75 to 80gr slugs. Same ballistics, less recoil, and cost.