1.) Is there an affordable way to do text only chat for unlimited users?
2.) Is it less of a headache to outsource for management?
3.) Are all costs based on the number of users?
4.) Is there a way to pay one price to have installed on more than one site?
1.) Absolutely, we use an open source free chat script in which we modified to integrate within our sites which supports unlimited users.
2.) I wouldn't say that outsourcing for management is always your best bet as a well developed website is usually simple to administer from an admin panel.
3.) No, in many cases the more users you have the more revenue potential you will have, however the more users you have the more upkeep is required for the website.
4.) You can always pay one price for a website to get all of the bells and whistles it really justs depends on which provider you choose to run with.
I would be glad to assist in the development of your project, I run
Vessio, just shoot me a PM! Best of luck, I hope that I answered your questions.