You paid what anyone with any vehicle might pay for any random part of the same size.
Not all random parts, but some random parts.
I typed in a random brand of car and the words "ac knob" I've never owned a toyota but they're as common as cat hair.
This is the first knob that popped up.
Shipping would be the same as you paid.
(and knobs are available for Thor ac as a set for about 5 bucks(ish) on amazon and ebay.)
I'm sorry I missed your post here on the forum asking about where to buy the knobs.
There's no reason to be mad. Some poor single mom in a $2,000 claptrap RAV4 just paid 25% more for the same thing.