I highly recommend Square for credit card transactions! I've been using it for a little over a month and I love it! PayPal charges $30/month for their credit card services as I recall (+ a percentage too, I'm sure!). Square is just 2.75% of the amount charged! The money is in my bank account within a couple of days! www.squareup.com (NOTE: it only works with iPhone/iPad and Droid at this time ... yep, I had to go buy a new phone (Droid) but it's been worth it!!!)
I've done craft fairs for YEARS (umm, like 40 years ... I started very young!), but this is the first time I've ever been set up to take credit cards. It has REALLY helped sales!!! Especially with the current economic situation and people not wanting to spend money ... one sale I remembeer well was going to be a $45 sale; the couple was expressing interest in another set of dolls and I told them I'd take $150 for them if they bought both (had been priced at $85 each); I don't often do discounts, but since I'm laid off, all money is good money! Anyway, they ended up spending $205 by the time they were done! At another sale a couple weeks ago, one customer spent nearly $400, also because she was able to charge her purchases ... she came back to my booth 3 times and found more to buy each time!
And yes, as for how much to take, take everything you have done! If things start selling like hotcakes, you could always take a few things OFF the table since it sounds like you need quite a bit of stuff for another obligation in the near future. But don't crowd the table to start with! And I hope you meant a 10x10 booth, not a table. That would be one huge table (and how would shoppers reach to the middle of it?). LOL!