Newton here. Barrett avoids humanity. I told him he has to spend some time handling support on the CartThrob forums and he told me:
it goes against everything I believe in when it comes to forums….. lurk quietly and never post.
ANYWAY. 😊 CartThrob has no monthly fee. It’s a one time charge of $100.
CartThrob has an auto-install system to do basic configuration. You can have a t-shirt store out of the box, and samples of other types of stores… software, donations, single page checkout.
It comes with several common payment gateways. If you use Paypal Pro, Authorize.net, TransactionCentral, SagePay, eWay, LinkPoint or Quantum it doesn’t take much effort. If you’d like another payment gateway, you can request one, and we’ll get to it in our own time, or we have a flat fee service for gateways that is very, very reasonable.
If you’d like to hear a bit about how CartThrob works, take a look here:
http://cartthrob.com/docs/sub_pages/choose_blogs_to_store_product_data_orders_and_coupons