I'd like to put a dab of money into an online venture - But what??

Hello, everyone...
I have put back about $60-$70 on a credit card just for an online venture, but I am not sure WHICH one to put this money into.

Important Side Note: I think I might have mentioned it on another posting that I'm trying to be both "Mom & Pop" right now, so it is doubly important that what I do w/this I don't just lose, so I want to be really careful - but I also want to have fun! And who knows, along the way I may just make some real money!

I'm open to ideas & here are some things that I have thought of:

The new autosurf put out by the owner of DadnDaves (David Cannard) (No name here, so I won't violate any TOU's)

Maybe become an affiliate of a good program (ebay?) & learn to do a google adwords campaign to earn by it.

Last, but not least, I also did think of running a niche-specific classified site (Thanks, Phil! ) using google to earn revenue on.
I'd probably have to invest in a BB software to run that.

Anyway, all suggestions are appreciated! I've wanted to set some money back for this for some time, just didn't have it to set back...now got a dab & would like to make something out of it & "grow it".

Oh, my last thing would be to 'think' of buying the rich jerk's material...

Thanks for your input!