I know you said you don't drive, but I buy a lot at garage sales...it comes in handy for piecing, and you can't beat the price! Tell your friends/family to watch for you when they go..tell them your top price per spool you're willing to pay...and set them loose! I got an entire shoe box chock full of thread at one sale for 2 dollars..they might enjoy surprising you and getting you little what you want..in my experience..people that go to garage sales a lot like the hunt! If you give them an item to hunt for, they will deliver!
I also watch ebay...but that hasn't been panning out too well lately because the cost of shipping kills any deal I might have gotten.
Connecting Thread is cheap enough..but the lint is unbelievable! I have about 20 spools that I just cringe when I think of using it! It's fine on the older machines, but the new computerized machines do not like lint!!!

www.redrockthreads.com has a good selection of threads and good prices. I like the Aurifil mako #50 thread for piecing and #40 for machine quilting. King Tut by Superior threads is another favorite for quilting.
Sharon W. in Texas

I was always told to use cotton thread on cotton. According to what I have read here it seems some use poly as well. It doesn't cut the cotton material?

I usually buy my Superior threads, and others, online from sewthankful. They are prompt, have excellent prices, and have a good stock. I live where quantities (cones, etc.) of "good threads" can't be bought for more than 100 miles. Sewthankful has free shipping with a $100 order. If I don't need that much, I can usually find someone to share the order.
Joann

Sewthankful often has Superior Thread on sale. Check them out. Superior Threads has a newsletter and Deal of the Day, which is when I purchase lots of thread on sale. They also have different thread clubs, where you can get deals as well. I use a lot of Bottom Line and So Fine for piecing. If you want threads that blend right in for quilting, I use those two.