Right now at JoAnn’s they are having a Yarnormous Yarn Sale (give this link a minute to open- this page is REALLY struggling or you can go here to the main page and find the sale) with prices starting as low as $1.99. Plus shipping is FREE on orders of $25+.
There seem to be some really good prices but I know nothing about yarn so take a look around- you might find exactly what you need!