Domain Name
You need to think of an appropriate name for your website. This is known as a Domain Name. You should call your website something relevant to the products you will be displaying. Have a few names in mind and use the search facility at 123 Reg.co.uk to find out if it is available to use. Remember every domain name is unique. Also do not use brand names as part of your domain name. For example, ToysRus or any football team name etc. These large companies will take legal action against you if you use their name as part of your website name.
Domain names should be easily remembered and not too long! From experience hyphens in domain names are not as search engine friendly as others. So avoid, one-to-buy.com and similar examples. Numbers are popular. So play around with various possibilities until you find a name that is real catchy. Put it into the search box at 123reg and see if it is available.