Ive sold a lot of stuff. This is what I have done..
If you own your own business and accept credit cards just have buyer call in with the number. You run the charge and send UPS tracking number same day. Buyer gets credit card fraud protection this way...you get your money.
I have also sent UPS COD before. This is great since buyer gets product and gives UPS driver the check. I usually will send from UPS store to UPS store. They are all over the place.
I have had buyers send me check, wait till check clears then send product. I have sold several items via Wetpixel this way. This is not good for buyer.
I would avoid Paypal/Ebay. They will not resolve any issues for you. The only time I've had a problem with selling/buying has been with Paypal. If you run into a problem you will probably never ever speak to a real person.
Western Union is another method of a buyer sending you money. This works good as well.
I have never had a problem with someone from wetpixel buying my camera gear.
M.