I'm convinced that you can get as much out of a relatively inexpensive home sewing machine as a costly, professional model. The trick is to understand your machine and take good care of it.
Like any piece of equipment, your sewing machine needs a little TLC from time-to-time to prevent damage to its delicate parts. Taking good care of your machine will help you, the sewist, to better understand your machine and, if you can keep things running smoothly, preventing many of the frustrations that pop up during projects.
Before you do anything, track down the manual for your sewing machine and READ it. Technology has moved on in a big way since your 8th grade Home Ec class, and your manual will show you how to clean the bobbin case on *your* machine.
Let's take a look at my bobbin case and see what's happening in there. Even the finest fabrics and threads have slubs that leave fuzz inside your machine. Too much fuzz can upset throw off the tiny parts and keep the needle and bobbin from doing their thing.
My sewing machine came with a tiny brush. I got a little bit of fuzz, but since I have cleaned my machine in awhile I decided to remove the plate, just to be sure.
Gross. Those little "worms" to the right of the bobbin are fuzz that was packed inside the grooves between the feed dogs. Take five minutes and clean your bobbin case before you use your machine. Get in the habit of checking the bobbin case regularly, especially if you sew fuzzy stuff, like felted sweaters.