I give this a big fat “NO!” Ask them if they would work for free. It’s disrespectful and unprofessional for them to even ask you to work for free with the carrot on the stick being a possible job.
Also, this was brought up in another thread, be careful about being so focused on creating products that you love. Your employer doesn’t care. They didn’t hire you to grow and be personally fulfilled. No, they hired you to do work that results in them making money. Don’t want to come across as Debbie Downer here but that’s unfortunately how things are. If you want to be creative beyond the work you do on an 8-5 basis, do side projects for yourself. These can be incredibly rewarding and educational.