I'm required to wear prescription safety glasses at work,I have a pair clear and dark glasses.
Walmart eye care center is the cheapest place that I've found over the years,I think I paid around $70 a pair for them,and insurance paid most of that.
Texas State Rifle Association
North American Hunting Club
These all have prescription inserts you can use and just change out the safety/tint lenses as you please. And when your prescription changes, you just change out the inserts and not all the different colored lenses you have.