I think the answer is, "It depends". We have many questions from people who could as well be freelancers (questions about going over time or over budget for a contracted project for a client), which we are more than happy to keep open here:
These are just examples, but to me these could all be asked by a freelancer and wouldn't make the question any less appropriate for our site.
If your questions are more about the nitty gritty of freelancing in specific, "How do I create an invoice?" or "How should I provide a cost breakdown of a project to a client for evaluation?" or the like, then Freelancing.SE (a Stack Exchange Beta site) may be a better place. Just be sure to read their help first.
Basically, if you want to ask here, I invite you to. The worst that happens is that it gets closed and/or moved to freelancing.se instead. There are many questions that can be on-topic on multiple sites on the network, and that's perfectly okay, so ask wherever you feel most comfortable and it will help us define our scope, and also help you get a better idea of which questions fit where best.
Look forward to reading your questions!