Oh there's no need to spend hundreds, NS glass just doesn't suit my eyes, & that is the main issue, you need a scope that your eyes can get on with & the only way to know is to look through it.
But going back there really should be no need to ever shim a scope if/when you have half decent mounts.
Again the cost of mounts is relative, some people think £20+ is expensive, it's not, even BKL's at £50 are cheap compared to quality CF rifle mounts.