Well, I told you they were pricey, and Megaman is kinda on the pricier side (Megaman is a popular franchise) so here goes:

Mega Man 2 -$850
Mega Man 3 -$700
Mega Man 4 -$750
Mega Man 5 -$750

GameBoy 
Rockman World -$750
Megaman 2 -$750

GameBoy Advance 
Mega Man Battle Network 2 (debug) -$400

GameGear 
Mega Man -$750

SNES 
Rockman X3 sample -$1000
Mega Man 7 -$750
Mega Man Soccer (no gameplay)-$250

---

I know for a fact that Rockman world is early and is an English Japanese hybrid and Rockman X3 has a lot of differences. No idea on any other protos.

Let me know how much you can spare on each proto and we'll see if we can work something out.