Hi,  Check out our section dedicated to information about taxes. Our blog post, "When does a Business Start Paying Taxes?" should offer some good resources, as well. 

How you declare your earnings will depend on the business entity type you registered with your state or county. You have registered your business, right? If not, you need to do so before conducting business. If you registered only a DBA, then you will file a Schedule C with your personal income taxes. On it, you will list all your income and your expenses (web site hosting, cost of products, etc.). You will pay taxes on the net profit. You will also have to pay self-employment taxes if you make more than $400 in a year. You calculate and file that with your personal income tax return. You may need to pay estimated taxes as well. They are paid four times a year on your income unless you have adequate withholdings from another job. Be certain to keep accurate records of all income and expenses. You should also open a business bank account.