I bought a used Genisis 29er coaster
 

...and all I can say is I'm glad it was only a few bucks! I thought the square taper crankset would be a sign of a better quality bike. After a repack, I stripped the lock ring. And after repacking the headset, the adjusting nut still turns with the locknut. The washer is keyed. Then I repacked the rear hub, and it screaches. I used a lot of wheel bearing grease too. I keep reading that budget cruisers are very serviceable. I am not convinced 😚