You will only owe tax on the profit you make on your business , not the sales amount. You have to treat it like a business and not a hobby for this to 'fly' with the IRS. You need to depreciate equipment used according to how much use is personal and how much is how much business use. You can only deduct the supplies used in the sold product. Other amounts are inventory assets or personal supplies.
Any profit will be subject to FICA, ie social security and medicare, at 15.4% and your income federal and state will be taxed at your marginal rate when combined with your full time job income