Originally Posted by
himespau
If memory serves, Denalis don't use cassettes. They use freewheels, so you're not going to find one with a cassette. Just find another cheap bike on craigslist that has a working rear wheel with the same number of cogs (and is the same size) for $30 and swap the wheels. Then save the other one for other replacement parts as yours break.
+1
This is likely your cheapest option.
Sometimes people upgrade their wheels and sell the old ones for cheap.
I sold the take off wheels from my hybrid for $50 on CL. MUCH better wheels than on you Denali. These had the spokes properly tensioned and should last for decades.