FWIW: a complete 700c coaster-brake 3-speed bike (w/Shimano IGH) can be purchased for around $350 from at least 1 source on the Internet in SoCal, apparently with free shipping. Professional assembly is recommended by the vendor. Probably low-end frame and other components, but might fit the customer's needs if a wheel turns out prohibitively expensive. He or she might also pay you to do the assembly.
Other sources list non-coaster models for even less. Not sure about shipping costs or locations for those, though (didn't look).
Last edited by Hondo6; 09-12-21 at 08:43 AM.
Reason: Add info inadvertently omitted in original.