T.C.
You could go ahead and buy a regular sewing machine, sometimes the lower-end ones are less than $80. Sears, Walmart, Costco, and craft stores usually have them where you can look at them. I got a good deal on one from HSN. It was a Europro brand, and had a nice storage case built in. It did break though, because when my son was little he put pins inside the moving parts. After that I bought a basic brother machine.
My son is now 8, and he knows how to use the regular sewing machine. To be safer, he likes to either turn the wheel by hand, or use the button that does a single stitch at a time. Because there are dotted lines and arrows printed right on the machine, he can do all of the threading except the last step of going through the needle. He can wind a bobbin and put in the drop-in bobbin. But if it gets tangled, he needs help.
We cut up old tshirts into 6 inch squares, and he sewed on yarn and other decorations. I sewed them together to make a very special quilt for him.