PVC/Vinyl tubing available locally may hold up for a while but it is likely leaching into hot liquids. What I'd suggest is dropping a 2" section of it in some boiling water and letting it sit for 10 minutes. Cool the water in the fridge and drink it. If you don't like the taste, I'd skip that.
If money were no object or you were a savvy ebayer, the best stuff would be reinforced silicone. There are some 5/8, 7/8, and 1" ID rolls of it on Ebay right now for about $2 a foot.
I use 1/8" wall silicone and it's fine. 1/2" ID, 3/4" OD and I got it from USplastics when they had a free shipping promotion. B3 and AHS have the same stuff.