My youngest granddaughter was 4 when she decided she had to sew- I bought an inexpensive Brother machine from Walmart ($89)
the best thing about the machine was it had speed control- I set it on ( turtle) speed and it didn’t matter if she became foot heavy it still just poked along. I set the machine up on her little Care Bear table so everything was set up for her size. Her daddy was being deployed and she had to make him a quilt to take with him so he wouldn’t forget her. She did every bit of that quilt herself- I even tipped a tall dresser on its side for her to walk on to longarm quilt it. 15 years later she still has that machine- makes purses, gifts, toys sometimes and her daddy took that quilt to the Middle East and is retiring this year- he still has that quilt- never leaves home without it
all the kids in the family started sewing on inexpensive Brother machines and I know at least 5 of them are still being used years later