Welcome! For bargains, in addition to thrift stores, look at garage sales, estate sales or auctions for things being sold from sewers. You'll have to learn to judge by feel what is 100% cotton as you usually won't have fabric labels but sometimes you can score some really good finds. I recently found 3 yards backing fabric about 90 inches wide in an antique/craft mall where people have booths. I paid only $3. Don't overlook CraigsList or freecyle online, as mentioned above. It is not as active here in my rural area, but in larger towns there are often great deals!