Is there an free way to test Avalara and CertCapture APIs?

Anyone has experience with testing Avalara and CertCapture APIs? I noticed the production integration broke might be caused by some recently Avalara API update but when I try to test with sandbox. I was billed $140 for the sandbox account. Is there an easy way to test or I will have to look for a substitute solution? Charging for a sandbox account is definitely not startup and developer-friendly!!!