Re: quality budget glass??
In that price range you are looking at either a Nikon Monarch or Bushnell Elite 4200, both of which have been discussed many times over on this forum. Both are great scopes with there own respective pluses and minuses. IMHO, going any lower in quality than these two scopes is a waste of money
Incidentally, I am in the same boat as you...looking for a scope to shoot my 260 rem out to 600 yrds as well. I settled on the Nikon Monarch 4-16x42SF with mil dot reticle (can be had under $350) because of all the great things I heard about it's clarity and generous eye relief. My problem is that I waited to long and now think I need something more than 16x for 600 yds...so I've started my search again.
Your third option would be to look for a used Leupold VX-III (not a VX-II or vari-x). If you watch ebay long enough you can snag one for a decent price.