Our children have been going to the Lowe's Build and Grow program for several years now. It is totally free and is geared towards children ages 3 and up, but even our 2 year old loves doing it! Lowe's Build and Grow clinics are on the 2nd and 4th Saturdays of each month from 10 am to 11 am. You can check out their website to see what projects are coming up and to register for that project.
Walk-ins are also welcome, but they sometimes run out of kits if you don't preregister. Each project has precut and predrilled wood pieces and comes with instructions. They are very easy to follow and put together. Each child participating also receives a free work apron, goggles, a project themed patch and a certificate of merit once they have completed the project. It is a great way to build confidence in your kids while also teaching them how to follow instructions, hammer a nail and project safety to name a few. I love seeing their faces as they show family and friends the project that "they built". Home Depot has a similar program that is once a month, check out their website for more details!