Bicycle, bicycle, bicycle
Using messaging apps to sell goods has perks and drawbacks. The ease of use and the ease with which any potential customer can get in touch with you are both positive and negative aspects of the situation.
When dealing with lowballers, you must display great patience or act as though you don’t understand their question and give them an answer that they don’t want to hear—even though it’s also technically correct. This is what the individual above did.