Market charging me $3??
I suppose it was bound to happen eventually. Let me first say that I already knew about the Market hack where users can "buy" your app, then request to cancel within 24 hours for free - but they've already gotten the download! I protect my apps by requiring a registration key even on my paid apps in the Market.
But what I didn't know was, as the late Paul Harvey would have said, the rest of the story. If your paid app is less than $10 the user can request a chargeback which will be automatically approved by the Market - at a $3 expense to the developer!
This is a crazy policy for Google to have. I suppose the upshot of this is that my next app, WordBox, will have to be on sale for $10.01 in order to avoid the automatic approval of the chargeback. If I get a couple more chargebacks on my $0.99 apps I will simply pull them from the market - I have to sell 5 for every chargeback just to break even!