I have had that $49 Brother for about 4 years now. Not a repair needed. I have made 1 queen size quilt and many many rice bags, halloween costumes and a little of this and that. I did have to buy different feet for it. $8.
If you plan on using it hard, I would try to upgrade a bit. Mine tends to shake when I run it hard for an extended amount of time, but.....it has served me well. And IF it does break on you then the money lost shouldn't be too heartbreaking. I am about to upgrade, but I think I will keep this one around for backup.