Pocket Reversi was relatively cheap, it was still the most expensive game I bought.. picked it up from ckchan for $140 dollars, which was about £70 at the time.. I miss the 2:1 exchange rate lol.
The only cover variation I bothered with was Samurai Showdown 2
The B&W games I got really lucky, picked up Tennis and Neo Geo Cup for just £10 each from a Spanish website called nkplayers.. the others picked up on the forum..
My favourite find was a clear blue slim console, a chap responded to my wanted ad for a PC-Fx and when I went round his house to pick it up he had loads of other cool stuff.. so I got the PC-FX a white Saturn and a bundle of Neo Pocket stuff including the slim console.. I wish I had more cash on me at the time..