Where can I purchase print wheels (daisy wheels) for the Radio Shack
DWP 510 Printer?
NOTE: Radio Shack no longer stocks these (unless you know something I
don't).  I managed to purchase one on eBay, but haven't had any luck
there lately.

Hi - I own a Franchise Radioshack in Oregon. Parts are often available
after product discontinuation. Enterring the original part # for your
printer (260-1270) in the search field at RadioShack.com will bring
you to such information. These part #'s can be orderred at any
RadioShack or at 1-800-THE-SHACK.

See:
http://support.radioshack.com/support_accessories/doc30/30624.htm
for a detailed parts list for that printer.