One could at least try to estimate their personal cost of wearing a mask by considering the following:
Suppose my chance of getting sick at EAG was 0%. How much would someone have to pay me to wear a mask?
If we're talking about the entire conference, I think I'd need to be paid at least a few hundred dollars.
For me this would be a way lower cost, yes. But it's very contingent on what the workshops are like. Just listening to someone speak and a Q&A? I'd do it for like $10. But if it's speed meetings or anything with significant face to face interaction I'd need to be paid more.