Charging for A Live Chat Service

I run a wordpress website providing free legal help. To fund the site I want to place an instant messenger service, whereby, for a small fee, someone can get an answer to their question right away.

Is there such an app which would do this? They type in there question and it comes through to my mobile device maybe, if I'm out and about.

I then tell them if I will accept the question and send them a payment link to Paypal perhaps? As soon as the payment is made I give them a full answer and e-mail them within 24 hours with an even fuller response.

The problem with sending a paypal invoice each time is that I will have to draft a fresh one each time somebody contacts me with a question, surely?

If anyone knows of any app that may be able to help I'd appreciate your input.

You can always have a question and answer community script setup to easily maintain and manage the same idea and hide the question or delet it once it's answered or move them into an ad supported section in which people would pay for a frequently asked questions section.

You can set up a few different paypal payment links for different amounts. Then set the links up as canned messages in your live chat app. So instead of typing the whole link you'd type something like pay_100 to insert a link for $100.