Easy Money
One of the best ways that I have found when it comes to gaining money is doing the liberation missions over and over again. It may get boring after a while, but it racks up money quickly. Another way is to use the navicust program Millionaire. (I think it's called that. I know for a fact the name is something along those lines)
More tricks, tips and cheats for this game are right here - Mega Man Battle Network 5: Team Colonel cheats
Comments for this hint