Ask HN: Best payment solution for a non-profit looking to accept micropayments?

I'm the webmaster for a small, non-profit student group looking to bring fundraising online. The fundraiser involves taking small payments ($1-$2) from students via credit card. I have previously worked with Stripe, but I am hesitant to use it for this situation because it will turn $1 into $0.67 and $2 into $1.64, which is a big drop in charitable donations. I am looking for something extremely easy to set up that I can integrate into a form on a Ruby on Rails or Sinatra based website, but that won't charge the same high fees on such small charitable donations. What are some of the good options here?