Ok, we can work this one out. According to another post here the odds are about 7500/1 of a hole in one.
Lets say the field for a tournament is 200. 200 play the first two rounds and then 100 make the cut and play 4 rounds. That makes a total of 600 rounds. There are 3 or 4 par threes on a course. Lets take 3 par threes for example. 600 x 3 = 1800.
7500/1800 = 4.16.
Bookies will never give you that price so I'm going to say 3.50.
Does that make any sense? I'll have a look at the next major and we can compare odds :)
All the best, Shane.