You should try the real cost of selling plants on E bay.
I have sold a few without reserve, and with £2.50 P&P I have ended up
making
less than 50p on a plant.
There is the listing charge, the selling commission, the cost of accepting
payment by card, Box, packing time, and Postage, not to mention time and
fuel to get to the Post office.
Not the way to get Rich.

And I have had a few good buys on line as well.
Though my Variegated Horse radish this year is plane green,


I have thought about selling some surplus plants on Ebay but it is
definitely worth being very selective and see what buyers are prepared to
pay 'lots' for ;-) But it is a good way to buy plants, from my experience!

Off topic - last year I sold a lot of old Lego, that had belonged to my
children, on Ebay. It is amazing how much I sent to Japan!

Natalie