Source for revolution med?

Hi Kitty folk,
Anyone have an "underground railroad" source for Revolution to fix
kitty ear mites? The whole pride of 6 has them and my small supply of
Acarex get's em but they keep passing them back and forth. The vet
wants a check up for each cat so I can't spend almost $500 for $85
worth of medicine. Do places like "Pet meds" require a perscription
for this? Please help, the poor critters are not themselves with this
going on..

I searched google history but it's not working.
Thanks, Karl.