It depends on the day and the hour. Outside peak it is usually 10-20 minutes, but on a weekend morning heading to Greece and on Sunday afternoon heading home it can run to 1-3 hours, especially now with the new biometric control (EES). On this page you have live cameras and the current waiting time.

Bogorodica is the main and fastest one for Thessaloniki, Halkidiki and Athens, but also the busiest. When it is jammed, Star Dojran is a good alternative for cars (fewer trucks) for the eastern coast and Thessaloniki. Medzitlija is for western Greece and if you are setting off from Bitola.

You need a passport. Greece is in the Schengen area, so an ID card is NOT enough to enter. With a valid biometric passport you can stay up to 90 days without a visa.

The price is regulated and the same at every insurer - it depends on the engine power and the term. For a car up to 66 kW it is ~1,850 denars for a month or ~3,690 denars for a year; over 66 kW, ~3,075 denars for a month or ~5,536 denars for a year. The shortest term is one month (there is no 15-day option). Get it in advance from your own insurer - do NOT count on buying it at the border, there is no desk there for the exit to Greece, and without a green card the Greek authorities can turn you back.