Sorry for my bitchy comments
If you're short of money than just get yourself a ordinary set of bikes. They're half the price of the fancy pants ones, which I've personally never really seen any point to. I've only ever used ordinary bikes (except for my pink bikes) so I don't know if the quality is any different but I wouldn't have thought so.
How about branching out into something different, other than cards. I noticed that there are sponge balls on that site, they're great fun to perform, easy and people really love watching them. Or there's coins, they wont cost you anything.
Just some ideas for you....