How big is the market for Scala programmers vs Java programmers vs Python programmers?

Anecdotally, with a SF/SV centric view point -- There are a lot of really good java programmers. If you know what technology stack you want to use, you can probably find someone who claims familiarity with it. However, *everyone* "knows" java and you'll be flooded with bad leads. A lot of people have used python in a shallow fashion. Considerably fewer have used it in depth or as a primary language for a long time. Scala is "hot" but not many people have any substantive experience in it. However, if you explicitly want to hire people to work in scala, you'll have fewer people to weed out. Comp wise, I actually don't think there's that much of a difference. People of a certain caliber tend to cost the same across languages. If anything, you'd probably end up (relatively) overpaying most for mediocre java programmers as they always have an out at some big company where they hit all the right HR buzzwords.

If your only question is to land a job, go for C#/http://VB.Net, following by Java accompanied by various frameworks. Adding JavaScript with jQuery is will further help. Don't take my word for it, go to your local recruitment site and filter job ads by programming language. Only look for junior jobs, as senior jobs require either lots of experience (you can still earn a lot of money by doing COBOL on some old system). If it should be dynamically typed language, I believe Ruby and Perl are more popular then Python. It looks like Scala is still in stage where projects are started by enthusiasts, either in startups or in pockets of enthusiasm inside large shops. With Python you have Google effect - it is used by Google and companies that want to be like Google. If that is your thing, go for it. And, finally, even from pure jobs perspective the right question is what language is on its way up. That will give you the second job of your dream. Not Java. You will be competing with good programmers with 10 years of experience.