It seems like normally when you look at two different weapons or pieces of armor of the same type (handguns, punch guns, shields, whatever) that if one looks better one way (more damage) that it's going to have a defect somewhere else (more stars and thus takes longer to level up)
BUT the Proto Gun and the Stun Gun look absolutely identical in damage and speed (including the charge time and attack speed: ultra bonuses), except that the stun gun causes stun while costing the same amount
I can get behind the idea that many pieces of equipment of a comparable tier will all cost the same amount (200 crowns for a proto gun OR a proto bomb OR a punch gun.. etc etc) but when one item is flatly superior to another shouldn't there be some difference in cost?
You get the Proto Gun for free at the start of the game. If you lose it and for some reason, want it back, I don't see why you shouldn't have to pay 200 crowns.
I mean, you're already into masochism, so why not?