Can we work on our games before the jam starts? Or can we only work on them during the jam time?

Also, if we later want the game to be paid, should we set the game to have a 100%-off sale during the jam time, or should we set the game as free to download and then change it to paid only after the jam?  Sorry if this is an odd question, I've just heard from other people that if you set the game to 100%-off that it doesn't show up under the free category.

Thank you!