Time to start going through your old Magic card collection. Or paying a little extra attention next time you're at a garage sale.
A rare "Alpha Black Lotus" card, from waaaay back in 1993, has gone for $27,302 on eBay, owing both to the fact it's rare (one of only 1100 printed) and also because it was in almost perfect condition.
If that doesn't stop you asking wwwwwwwwwwwhhhhhhhyyyyyyyy, below is a video that goes into way more detail.
Magic 'Black Lotus' Fetches $27,302 [What Sells Best]
HIGHEST GRADED BGS 9.5 ALPHA BLACK LOTUS [YouTube]