For my price point, being able to accept credit cards seems essential. I do a low enough volume that I couldn't justify paying the $20 to $30 monthly fees lots of companies have, so I use
ProPay, which charges a flat rate of something like $50 per year, but takes a bit higher percentage in transaction fees. For me, it was more financially prudent. If I was selling more months of the year, then I'd be real interested in an arrangement like Paul mentioned above.
Although ProPay offers card readers (for an additional fee), I just use the old fashioned manual card scruncher and do handwritten receipts. When I get home after the show, I enter the transactions on a website and the money is credited to my account in a few days. I don't verify the card before the sale. As I said, I do a pretty low volume, and so far I've not had any issues with getting paid. (I also accept checks without batting an eye.)