TeePublic does not issue 1099s, but ShareASale will issue one if you earn more than $600 in one tax year (total from all your ShareASale payments).
You can find your tax form under "Account Settings" on the 1099 tab. If your account is listed as Non-US or as a US Corporation you will not receive a 1099 through ShareASale.
Even if you do not reach the $600 threshold, you are still required to report your income according to US Tax law. We would suggest you refer any further questions on the specific taxation of your commissions and/or what to declare to your accountant or the IRS.