I splurged on a few titles. Here are few that are worthy and the price I paid and ceiling willing to pay:
> Nexzr - $130. I was willing to pay up to $150 for a CIB spine one. After I got it, I was so blown away on how awesome it is. I then got lucky and found another one CIB for 80 bucks bringing my avg cost to 105 each. (since then already sold it off along with my Bazzy)
> Bazzaru - $350ish paid for a unopened copy in a store, my ceiling was 200 but it was the only one I ever seen avail so i picked it up. since then I bought another one also sealed for 200. so avg out to $250, which I deem fair for a sealed version. still on the hunt for a loose copy cheap to play and enjoy the heck out of.
> Ys 1&2 US boxed sealed - $130. This one I would have paid up to 150 I think. I love Ys and it holds special value for me.
> Downtown Nekketsu - I would pay up to $200 for a gem mint condition copy of this. In fact after I traded mine to Hoobs I found one in a store which I dropped $160ish for.
>Sapphire - I paid $200 years ago on jp auction, got lucky it was gem minty with all inserts and not a bootleg. If the market is clean and I didn't ahve to worry about bootlegs, I would go up to 300-350 ish for that, it IS worth it.. prob the only Arcade CD that is worth getting the system card for too...
as for the rest of the titles, it depends on the completeness, condition, which the x-factor being my enjoyment factor/memories of that game.