Get something cheaper to shoot. Use it to work on your shooting form. Then shoot the slug gun a little leading up to season. I picked up a .22WMR a few years ago that I use to work on things like trigger squeeze and breath control, but others would work. It'd probably pay for itself within a year or two, and then you'd own another gun, which is never a bad thing.

OR, shoot the cheap rounds the rest of the year, then switch to the good one's for hunting and tweak your zero accordingly.