Just makeup a business name. You don't have to register it. Most companies feel better if they think they are dealing with a business rather than an individual. Just pick something, even if it just 'brucelee sales'. It does not have to be anything fancy...
Then later if you get really serious about being a business you can register a business name and get a licence. Most all of the people you see selling on ebay are just individuals such as yourself...
I sell on ebay and several other entities and use a business name and I also have a tax id, but my business name is not registered...