Where can I work from home making C# apps and get paid (or am I dreaming)?
Lowest-level entry would be something like http://www.rentacoder.com/ - bid on projects and gain reputation by completing them successfully. Note that you will be competing with (a) third-world developers who are willing to work for a fraction of what you would like to charge, and (b) complete morons who will underbid you by quoting $500 for a MySpace clone and win the project somehow.
Moving up the chain, if you are a decent salesperson with a few contacts, you can start developing a network and a reputation for doing per-project work for local and regional businesses. Usually this is web work or custom line-of-business applications. Many developers turn this into a self-owned business and it keeps them busy full time and well-paid.
Well, if you're talking about making apps and getting paid per se, you're not dreaming, it's already around the net. There are a lot of freelance coding sites abound in the internet, like Rentacoder, that bids out software projects to freelancers who work from home.
But if you're talking about making apps and getting paid enough from such portals, that may be the dream.
Some consultancy projects allow you to actually work from a place of your choice (e.g., on-site or at home). If you're entrepreneurial, you yourself could set up a startup in your own home.
Point is, there are a billion ways to do this (work from home) but a lot of them are more difficult than just looking for a job. The possible windfall if you're successful, however, might justify going for it in the first place.
Goodluck.
You realistically have two options.
Find a job that will allow you to work from home.
This is easier than you think depending on where you live and what sacrifices you'll make in terms of the job. Its much easier to land this type of position if you live near a major metropolitan area where there are lots of employers.
Freelance.
This one is tougher than you think. You either need a lot of customers or a small set of customers who will pay you a lot. Acquiring either usually happens through luck or more realistically, having a salaried job and taking your customers with you when you strike out on your own.
You could build a few apps that would generate money in their own right and live off the income they provide? Perhaps a hosted service or something with a monthly rental?
Don't bother with rentacoder.com, guru.com, etc. unless you really can "create a stackoverflow.com clone for $50"
Instead, go to dice.com, click on Advanced Search, check the checkbox for Full Telecommute, add some keywords if you like, click the Search button. Set up a search agent to email these to you every day. Apply to the jobs that look interesting, call after 2 days to make sure your resume arrived.
You can also canvas businesses (local or otherwise) to find some that need some development work done, and negotiate a contract whereby most if not all of the work is done in your office (i.e. at home) instead of on-site.