I can tell you that Jan Jan Paradise is easily the most common Super Nova Game and you can usually find a dozen of them for $10 a piece on Yahoo Auctions. These are prime conversion fodder
Jan Jan Paradise 2 pops up every so often for around $30-$40, people convert these because they sometimes find them cheap, though they're uncommon enough they shouldn't
Otome Ryouran is even more uncommon and usually goes for around $80 (sometimes less if it's being sold by someone who doesn't know what it is).
Tel Jan is arguably the most rare SuperNova game. I own one, and the only reason I own it is because I bought the only one I've ever seen; probably paid more than I should have just for the sake of completing my SuperNova collection
If you decided to go for a complete collection like I did, Tel Jan will likely be the last game you find.
If you seriously want to play any of these you'll also want to pick up the MAJAN adapter so you can use a proper mahjong panel