How much is the lowest price of pinterest auto - commenter?

Hello everyone.
I am really glad getting useful help from this community.
What i want to know is the common price of pinterest - auto commenter price?
usual price i know is around 50$ and wonder it is common price.

I am a senior programmer in china and recently i developed my own desktop app which has functionality for pinterest and just want to sell it.

But i am new to around world marketing here, don't know how to .

Please share your knowledge with me.

Have you considered of making a legit full pinterest bot besides auto commenting too OP? Like following/liking/pinning ect ect.