If you represent yourself as a business, IS: business cards, bank accounts, etc, then you will need a tax ID and will have to file taxes as biz!
If you make more than $600 a year selling items, be they yard sale, online, craft shows etc, you are to claim it as income!
Under the NEW tax laws small/home based businesses are no longer allowed to claim utilities, mortgages/rent, phone, insurances, etc, etc....there are NO deductions for small home bases businesses any more!
Hence the reason I am closing my ebay store after 9 years!