It's a fine line for sure. You don't want to rip yourself off. Be sure to recover your costs, including utilities AND pay yourself a rate you think is fair. What ever that per cookie price turns out to be...is what you should charge.
Granted, lots of people in my area wouldn't even think about paying $4 for a cookie. But, somebody is buying them. They are all over the internet for sale! I guess you gotta find your buyers.
I once read a lady on here who said: "work smart, not hard". It made sense to me. If you undercut your price to something that doesn't feel fair to you....it'll show in your work, or at least in your heart.