Hi Miranda,
Your timing is out of whack. But rather than picking up another cheap-o, I would go to my local thrift shop or check craigs list and pick up a working older singer / brother / white sewing machine. I mean the old 19 - 00 pound work horses. I keep one threaded with black, all the time. Whip it out when I have a quick job using dark thread. Before going home with the machine, (I always carry a ziplock bag with thread & needles in it with 4 different kinds of bobbins... just in case I find a nice used machine to test) make sure that the needle goes up and down and the feed dogs are working, open up the lower machine and check to see the bobbin case (if it has one) is spinning. What this does is make sure there arent any broken gears. But if there are it wont be terribly expensive to repair the machine. Singers from the 70's & 80's are notorious for having nylon gears and the teeth chipping from them. What I would do is pick up even a non working one of them for next to nothing, drop about $125 into it at the repair shop, and then keep it as a good old stand-by. They form excellent stitches, handle heavier fabrics and you can use a mechanical ruffler on them without worrying. I have a 30 or so year old White sewing machine (all metal gears inside) that is a real champ, sews through leather, is pretty to look at, is respectable for free motion sewing, quilted beautifully, has adjustable presser foot pressure control like the new Janome's. A beautiful machine... and I only use my griest ruffler on that machine because everything else I have is electronic and more sensitive and I am afraid I would damage the machines using it. (call me a worry wort) LOL
I hope this is some help to you.
Good luck.
Paula
(I know it is easier to drop another $57 into a cheap machine, but in the long run, you will be happier with a vintage singer or white... and I am not talking about the old old 50 - 60 year old black behemouths either!)