Merchant account would be best.

But for short term you could check out ccnow and 2checkout.

They both accept credit cards and paypal payments.

Does he need help with designing the page for the order form, or with just processing the financial information? He needs to use a good merchant processor, maybe that accepts 'higher risk' eCommerce companies due to selling dietary supplements. I may be able to direct him to a few.

Does he actually want to create a CPA offer as a vendor and market the supplement via affiliates?

Or does he just want to sell with that model and style but not actually through a CPA network?

For health and nutritional supplements I would think something like Market health would be a good network.

They would have details about the responsibilities and fees for vendors.

He's not an affiliate or looking to get listed on a Clickbank type site.

He's an independent business/marketer who sells his own formulated nutritionals. And he's looking to run these cpa style landing pages. He already has a designer, he just needs the right shoppingcart/creditcard processor that works with these types of cpa offers.

The offer is that it's a free sample of the product but you must pay the shipping cost. It's not sold as a free sample though. Thus they enter their contact info to the form on the landing page, then that rotates to where they enter in their credit card information to complete the order. Hope this answers any other questions.

Are you looking for a high Risk merchant account? because Nutraceauticals falls under high risk business category.

Can't he register with CPA networks as a vendor and then get the affiliates to work out how, he just gets the information that he wants?