If you want to be serious and not get jerked around you need to go to a bank and request a merchant account. This wil cost a little startup dough though but nothing overwhelming.
Key bank asks for something like $500 in the account and $25 a month plus a $150 account activation fee. In my opinion though they are probably the best to go through because they are part of the NOVA network which means that you can process orders from pretty much any country using almost any form (credit, checks online).
They have software (php, perl etc) api's that will allow you to process orders from your site. Your server will also need to have SSL though in order to guarantee customer safetey. SSL itself is easy to setup but if you want to be professional you need a certificate from a trusted provider which will cost another $100+ depending on who you buy from.
You will most likely need a tech person no matter who you get a merchant account through. I am available for freelance hire though and my rates are reasonable
The bottom line here is though that you need to go to a bank, any bank, shop around and find the best deal that suits your business model.