Pick a name, any name.

Well, just about any domain name.  The best ones are all taken, and some good ones are for sale.  Chances are you can come up with one just suited to your website.  Find out by doing a search.  Type a name in the box and see if it's taken.  If you are successful, grab it quick.  There are thousands of people buying domain names for resale, even if they don't serve their own purposes.  

If your name is taken, it may be for sale.  But you may be able to make a variation on it.  For example, suppose you sell fashion shoes, but fashionshoes.com is taken. (It really is.) But fashionfootware.com isn't (At least it wasn't when I checked.) Or, though goodbuys.com is taken, GoodBuyToYou.com isn't. Come to think of it, We'd better buy that name.)  If you want a short name, like 3 or 4 letters, sorry, you're a couple of years too late.  In short, be inventive. Use hyphens if your name is cute, but try to make one without them. Happy hunting!