I have a full time job and my freelancing time is limited to 15-20 hours per week. For interesting projects I may consider to spend more time. Freelancing is not my main source of money, so I will not ask much, and can always negotiate. If you have an interesting problem I may help you for very symbolic payment.
Please do not hesitate to contact me with questions. I may help you solving your problem even if it is not explicitly mentioned in the description.