I have used Beanstream in Canada. They provide a hosted service, where you provide a link to a custom Beanstream page in your site; they do all the payment processing and deposit the funds in your bank account. You can edit the checkout page to make it match your site, and create shopping carts or provide charges on a case-by-case basis. I know you said you don't need a shopping cart, but it is only $10/month more.
They also provide a gateway API if you want to accept credit cards yourself, but I find the hosted service far more convenient.