My son somehow or another stumbled across this Polished Habitat where she discusses using a literature holder like realtors use to catch lint by her dryer.
My son did vinyl to make it a little more clear that we want this used and we hung it on the outside of our handicapped ramp, right in the dog walk area. Because of where it is, grabbing the waste bag is easy on the way to the trash dumpster every evening. It also gives us a use for the hundreds of plastic shopping bags a client brings us routinely.
We also found this handy dandy poop bag dispenser with a solar powered light we put right next to it for client convenience.
Easy, fast and inexpensive waste stations! Hope you find this helpful.