Ask HN: Any payment processing advice?

I'm in the process of building a simple website for my grandmother to showcase her artwork online. Right now, if someone sees art they would like to purchase, they send her an email and arrange a check or money transfer. However, I'm concerned about the risk of accepting checks and am looking into credit card processing systems.

So my questions are:

  - Is there really a risk to accepting checks, or am I just being slightly paranoid?
  - Should I go with PayPal, or should I look into alternatives?
  - What information do I need to keep for each transaction?