The best place to buy a domain is www.godaddy.com if you have a credit card or balance in your paypal account. If you are looking for some other alternatives to pay, then you will have to look elsewhere. I do prefer godaddy as the best source to buy domains as their control panel is something very easy to use and a lot of people are used to it, so its easier when u need to transfer domains due to a sale.

For newbies the price may seem high, but the trick is to use discount coupon codes while checking out. The code I use often for .com domains is ZINE3 which did work with my latest domain buy too.