I though places charging $30 to $40 were bad.
Check out these rates at Yellowstone Grizzly RV Park - -

https://grizzlyrv.com/rates/

Of course, $89.25 is for RVs only - no tents allowed.
Cyclists would have to opt for a cabin without bath for $109.95.
Cabins with bath go for the low nightly price of $179.95.
(Sales tax and lodging tax not included)

Why do they charge this much?
Because they can.