this may help... although it's aimed at FT scopes it should help with a few high mag scope options
the problem with cost is that large objective glass is expensive to make work with high mag scopes, because the mag pushes the quality of the glass. Couple that with the fact that high mag scopes aren't the mainstream for most scope manufacturers and you can see why the prices climb.
That said, 2nd hand there are some cheaper options. Normal catches apply with buying second hand, but if the normal precautions are taken then it could yield a good result.