From Pay With GasBuddy Terms of Service, Section 4. Enrollee Authorizations
When you conduct a transaction through our Service, you are responsible for ensuring that the funds are available at the time the transaction is conducted, and properly processed (posts) to your account.
Please note that your financial institution may charge you a non sufficient funds fee if you attempt to spend more than you have a available in your checking account. Please contact your financial institution directly for any charges or fees they may have.