OP, you might take a look at
2Checkout (or "2CO") - They are a credit card processing service that includes their own shopping cart.
Basically, you just put "Buy It Now" links on your own website for each item you're selling, with each link directing the customer to the shopping cart which 2CO provides for you on their secure website - They get the customer's name & shipping address, process the credit card transaction, and email you the details about the sale. After you mark the item as being shipped on 2CO's website, they direct-deposit the proceeds from the sale into your business checking account.
Since they handle all the credit card details, you don't need a secure certificate for you own website. You can use what ever domain registration service and hosting service you want for your own website.
2CO doesn't charge any up-front fees - Instead, they keep a small percentage of the proceeds from every sale you make as payment.