Actually Super Mario All-Stars is currently going for £18.99 on eBay, Very cheap indeed.
http://www.ebay.co.uk/itm/SUPER-MARI...b#ht_918wt_952
In my opinion, buying compete retro games for £50- is worth it. Especially if it's like Link to the Past. I like to play games on it's original platform as well more then VC or emulator.