Board Game Arena

Hi! There are three different bidding variants. Can someone explain what each of these means?

Scroll way down to bottom of the game screen and choose 'How to Play' tab.

We have just started a game on Mexico map with "No bidding - Worst is first" selected. After I passed for the initial bidding, I was given a bond and deducted $2K for going 2nd. Is that normal?

Samc1078 bid 4K before passing, so you pay half your maximum bid on passing