http://www.paulgraham.com/ideas.html
Phrase the idea as a question worth exploring: can I build a startup on the idea of [insert idea here]?
To quote:
> Treating a startup idea as a question changes what you're looking for. If an idea is a blueprint, it has to be right. But if it's a question, it can be wrong, so long as it's wrong in a way that leads to more ideas.
So what I suggest you do, is build a webapp based on some idea, but don't count on it making you much money. You'll still be getting experience and learning how to run and manage your servers (and that's really the core of your business).
$200/mo is quite manageable if you just put Google ads and have a decent amount of visitors. To do that, you don't need to have a business idea, you just need a site that provides some cool service that a decent amount of people would want to use it.
Point being, you don't have to hunt for a business idea.