Exactly! Several times a week, we see sellers who come here and reveal that they evidently had no idea of what eBay fees are and how they are calculated.
Even more scary is the fact that some of these sellers are not new or inexperienced.
The fee schedule is not exactly hidden, you just have to read it and price your items accordingly. Yes, calculating how to price your widget may take time and effort. But it's probably better than just making a WAG.