We do the same I think the last time we got it at the local Big Lots store
When ever I see it I get it. There is a hospital supply store near our home and they actually have sales a few times a year then we can get a whole box of tape for cheap money. the pharmacys have it too and if you keep an eye on the coupons for what ever is near you then you can get it cheap too.
I use hockey tape for injuries, my friend uses it for her shin splints and it helps her ALOT!
You can buy that at wal mart, target or like sport check.. I find it the cheapest at Canadian tire. but its canada and dont know if they have any in US.