There are plenty of professional online companies out there who will build a site for you.
But I would recommend having a go yourself, or at least attempting to learn something about web design and the processes involved. I say this for a number of reasons.
- It's always good to learn new skills. In a world where the internet plays such a large part, web skills are never a bad thing to know.
- It's fun! As well as your online store you might find yourself creating another site simply as a hobby.
- If something goes wrong then you will want to be able to sort it fast (since you're going to have paying customers). Relying completely on others to sort it isn't a good thing. It's always good if you know roughly how your site works so you can sort things faster (another reason to go to a professional company over some bloke on the net, they will be faster to respond if anything goes wrong or if you have any questions)
Here's a list of some online payment sources you might find helpful
35 Online Payment Services
good luck