I've been buying all of my cards through mtgfanatic.com for quite a while now (over a year); and it's been great. It's so much better than ebay or driving all the way to Wakefield to buy cards.
I've done side by side price comparisons against ebay and mtgfanatic.com always beats them. Plus, there's no ridiculous shipping charges. There's no worrying that your cards are never going to arrive or are going to look like they went through a shredder. You know you're dealing with a reputable business that's been around for a long time and has good customer service.
I know all of you have driven to a half dozen stores looking for a rare. After calling and being told they had it; you got there and they "must have just sold it." These guys have it. If they don't; you're not going to find it by wasting a tank of gas.
Plus, they buy cards and give a decent price for them. We've all walked into a store to sell a card and seen them selling it for $15 and they want to give you $4 for yours. Not here.
Their website is well organized, easy to use, and has a great search engine. You can bring up pictures of the cards. You can choose which version of a card to buy. Prefer 7th edition BoP to 4th? Want to put 4 versions of Disenchant in your deck? Not a problem. Get the artwork you want. Buy new or played.
To top it all off; every purchase gets you into a drawing for a $75 store credit. Who doesn't need $75 in free magic cards?
Give them a try. mtgfanatic.com.