I have agents going pretty much nonstop for hobby projects. This is great value for me because I get to see a lot of things I'm interested in come to life. It's very token-inefficient though and if usage limits were reduced much this wouldn't be worth doing.
For my actual job though, I don't let agents go for hours on end and I care about the code. I spend between $1000 and $2000 per month there. Of course we pay API pricing. I wonder how much you're getting for that $20 in API pricing, it could be 10x or even 50x. At least on the max plans it can be that high if you are hitting usage limits, I don't know about the 20.