It's certainly not easy, I'm sure of that- with the recent closure of the 3DS eshop, we've seen 3DS games soar in price, so I can't imagine what many GameCube games are going for these days. Back around 2016 when I sold my copy of Shantae, the "last game" I needed for my "Collection" was a game that the seller wouldn't sell for less than $700- that's when I realized that I'd never be able to continue buying retro games at those kinds of prices. Good luck to you in getting them back, friend!