I use WalMart ticking as well and also buy and cut their cotton flannel for cleaning patches...Ours stopped selling fabric about 2 years ago but there is one about 30 minutes down the road that does still sell fabric...I stocked up this summer when I had to go through there...

You mentioned Jo-Annes...Some use their cotton drill cloth, I believe they call it 40 cotton drill...It's used as pocket material in some pants...You might want to try that as well...