I agree with the Walmart ones for starting out.

Sometimes they offer a cheaper price one on Black Friday sale. But it usually has the same amount of stitches as the 89.-100. one.

I think I would go to the local sewing machine repair shop
or some dealers, and look at old used ones, then tell her
if she ends up not sewing she can give it back to you (ha, ha)
No, really I got mine at a yard sale, spent $45. to get in
fixed up, and it is my joy. Get a good basic machine, nothing
worse then being frustrated with the machine, then she
won't want to sew.

I agree. I don't think a 12 year old would want an older machine. I have an inexpensive Brother that I bought a few years ago to take to classes with me and I love it. Start her out on something that is new :)