Another vote for used PST w/ or w/o capped turrets. You should be able to find a decent mount in the $50-75 range and the scopes run $450-$500 new, so the combination on a used scope should be comfortably within your range. With Vortex's "no-questions asked" lifetime warranty, many of the typical concerns with purchasing a used scope just go away.
Thanks for all the input. I already have the Vortex Viper PST 4-16 and the Leupold VX-R Patrol 3-9. So some research and comparing the two, I decided to go with the Leupold VX-R Patrol 1.25-4