I actually built mine from scratch because the store bought ones just didn't fit right. I'm going to repurpose the other shelf to hold N64 games and controllers/accessories for all systems.
Back on topic some other games that I paid higher prices for would include .... Rainbow Islands for $35 (which I will keep with no regrets) and I nearly got Snow Bros. for $60 but took a pass and by the time I was ready to spend someone else had jumped on it.
I've paid higher prices for some of my Saturn and MVS games, but so far I haven't paid over $100 on a nes game. There are still some I want though. I almost pulled the trigger on $110 Cowboy Kid which I rented as a kid and really enjoyed but NEVER saw in a retail store. I'm sure I will eventually put that in my 480.