PayPal, Amazon and Google can be great solutions, one confusing thing to keep in mind is that YOUR customers are actually THEIR customers, all the customer data belongs to them, not you. If you ever want to switch providers or you grow into needing your own merchant account, those customers are "locked in".

I'm the Founder at Simplified Ecommerce, and our goal is to help solve this unfair situation for startups and Entrepreneurs.

http://SimplifiedEcommerce.com/aboutus