I have a basic Singer machine from Walmart that isn't the greatest in the world but for $80 it does quite well. The two brands that I have heard my family of seamstresses go gaga over are Singer and Brother with a heavier love of the Brother machines. I don't know what you consider expensive but Walmart and JoAnn's both have some very nice basic machines in either brand in the $80-$200 range.
Papa Smurf and Ramblinrev are both right about the bobbins, I always take one bobbin with me as well as the name and model of my machine to the store when I buy new ones. If you don't have that info, I too would take it to a repair shop.
+1 on Gutterman's thread. It is my favorite and the only brand I use for my backpacking gear.