what sort of salary do pros get with these contracts?
Depends, some of them will get 30 grand a year and some 20 grand until they prove themselves in the pro ranks.
With the exception of Phil Heath and Dennis Wolf who had a six figure contract right from the get go
Salary contracts have some heavy stipulations in most cases, you have to make appearances at expos and of course local shows, store openings and some even have you guess pose for whatever shows they decide to promote as part of the contract, sometimes 2-4 guess poses, like the muscletech guys did.
Also competing is a must, sometimes 2-3 shows and a qualification for the Olympia can get you a bonus so it all varies greatly and depends on your marketability skills and if you pull publicity, way to many factors involved to guess what the companies do
and they only give salaries to pros, no amateur ever gets a salary again with exception of Phil Heath