Are there any affordable DocuSign alternatives that do API access?

I haven't found a single DocuSign alternative that wasn't the same crazy pricing like $1.50/envelope or document.

I just want a simple mail merge on a document and send that to a customer to sign. I used to use SignRequest for that, and it used to be standard across the board, but all of them stopped offering their APIs in their normal SaaS packages; it's all under enterprise or too expensive.