St Andrews is a student town; one in three residents is a student, so it's quite hard to find part-time work when a huge proportion of the town are looking for it too.
As a town, living is quite expensive. Eating out cheaply takes a bit of searching for a good-value place, but they can be found if you look hard enough. Compared to the population size, there's a huge number of pubs in the town, and all of them attracting different types of people. If you're coming to St Andrews, I wouldn't worry about not finding a cocktail bar, or a pub to watch live football. You'll find one.
St Andrews doesn't have a train station, but Leuchars does and it's ten minutes away by bus so the town is easily accessible. If you're concerned about moving to a small coastal town, it's handy to remember that Dundee isn't too far away for a night out or a bit of shopping.