Paypal integration

Hi.
I am looking for a way to do the following, and wonder if your plugin can accomplish this task…
I work as a proofreader.
I’d like people to come to my site, paste in the text they want me to check, a word counter ‘sees’ there are (say) 1000 words (defined by the number of spaces), and then a paypal button on the same page automatically calculates the amount to pay – based on a preset per-word rate – then the user clicks to pay via paypal, completes payment to me, then I am alerted to check the text etc.

Many thanks,
Steve

https://www.ads-software.com/plugins/smart-forms/