Is Stack Overflow totally free for getting my answer, and when should I pay?

On Stack Overflow you’ll only get an answer if you’re asking a good question. That means a question whose answer can be of benefit for all programmers, contributing to the common knowledge base. Make the question clear, with a good title, short description with example code if needed. Put tags to correctly classify the question, etc. Also the question has to attract the attention of some Stack Overflow contributor able and willing to answer it. And don’t forget to check if the question doesn’t already have an answer, duplicated questions are very common on Stack Overflow.

If those conditions ar

On Stack Overflow you’ll only get an answer if you’re asking a good question. That means a question whose answer can be of benefit for all programmers, contributing to the common knowledge base. Make the question clear, with a good title, short description with example code if needed. Put tags to correctly classify the question, etc. Also the question has to attract the attention of some Stack Overflow contributor able and willing to answer it. And don’t forget to check if the question doesn’t already have an answer, duplicated questions are very common on Stack Overflow.

If those conditions are not met (ie: if you are looking for someone to debug your code, if you don’t bother to work enough on your question to make it clear and useful, it you are looking for someone to do your homework, etc.) the question is very likely to be closed fast and you won’t get answers. If it’s a good question, you’ll probably get answers, and probably more than one, and likely very fast. But again people are answering because they want to.

Also don’t forget to mark best answer as accepted. The answerer will thus get some reputation. It is also possible if you have yourself reputation on SO (which is unlikely if you are asking this) to set a bounty on the question, thus if someone give an answer to your question you will accept the question and he will get the bounty points on his reputation count. The catch is that the bounty is taken from your reputation.

No monnay involved in getting answers on SO or in asking questions. Also neither is paid except through reputation points.

The site monetize using other methods: ads, career, private Q/A services, etc. I don’t know if it is economically balanced, but nobody ever spoke yet of paying answers.

You should never pay any money to anyone on Stack Overflow, unless you are hiring them to do contract work for you, but that should happen using Stack Overflow Jobs, not the Q&A.