Assuming you live in the United States, the IRS usually wants you to report any income, no matter how big or small of an amount. That said, seeing as you're a minor, there's usually never a problem. The vast majority of people will not be making enough money to make it even worth reporting.
Services such as PayPal usually require you to submit tax information after $20,000 in G&S payments or 200 total transactions for G&S (per year); whichever comes first. Refusing to do so will put limits on your account, but as long as you don't hit that threshold, you're fine.