It's very straight forward:

1. They show you cheaper price. And from there the drama starts.

2. Then you provide the card information

3. Then they start sending email returning every time that the offered price is not possible any longer- overbooked. Start offering new price!

4. It's not done yet, they keep doing that several times....until you are offered a price which is a bit higher than the price you saw available.

What a terrific sight with people innocently telling lies!