Otherwise you can find an appropriately wide pvc pipe and ask nicely for them to cut it down. Local Menards did this for free when I needed some 8" pvc sections for snake tunnels. They cut a 5' pipe down, no questions.

For a general 16oz, asking them to cut it into 5" lengths should work, especially if you need multiples. Otherwise, you can get them to cut down the rest of the pipe for snake tunnels, climbing toys, etc. They're pretty used to this request at my place since people ask for similar cuts en-masse for things like DIY candlemaking.