What type of payment system should I use?
I have recently published several children's books which I want to promote and sell on my personal website. Can anyone suggest what would be the best type of payment system to set up?
It really depends on what fits your needs, but you have several good options available. Stripe (https://stripe.com) is a newer power house, PayPal (http://paypal.com) is a solid option that has been around longer, Dwolla (http://dwolla.com) is a new up and comer with lower fees and some interesting propositions. Of course there are other merchant services and exchanges but if you are doing this on your own you probably want to focus on the 3 mentioned above because they have lower fees.
I would suggest looking at the websites and researching the 3 above, but don't stop there. Talk to other entrepreneurs and publishers and see what they are using and if they are satisfied. The more information you have to make a decision the better off you'll be.
On a side note, did you write and illustrate the books? I have several children's books that I've written but haven't had any luck with illustrators. So any advice you have on forming a good relationship with an illustrator are also welcome.