I have a purewick machine and 183 external catheters for sale but I don't know who buys them? I'm asking $600 for all. Thanks for your help!

Yes, Nextdoor.com or craigslist.org

Try posting this on NextDoor. I am constantly surprised at the amount of personal care stuff that folks put up for sale with photos on the NextDoor app. Lots of infant / baby and end of the road items with meetup at Target parking lots. There’s a short story in there waiting to be written

Sorry, loves. This isn't a place to sell used items; it's a forum to help people participating in elder care.
Wish you the best.