Ive bought 4 of my 5 accounts trough www.gamersloot.net

good quick service, no problems at all so far..
even helped a mate of mine buy 2, no problems there either

as i replied in some other post
ALWAYS be sceptic (its a good feature), look around the site, see if there are contact info, a real life adress, and a disclaimer
check if there are pictures that show names of the bigger internet payement services, and secure payment sites.
see if you can pay by paypal (ALWAYS use paypal, safer, and easier to get a refund if the sale goes wrong), never use moneyorders.