Fiber tester recommendations - as low a price as possible

Looking for recommendations for a good fiber tester for testing signal quality/speed it will run at for some fiber runs that have been in place for a while.

I recently started a job at a small university and we are starting the process of replacing most of the network infrastructure as it is all pretty old. I'm looking for a good tool that will let me test the fibers quality and just test for activity (almost none of the fiber is labeled so currently which it goes to is based on traffic flows or guessing in the case of a bunch of the fiber that is currently unused).

Most importantly I don't have a ton of money for this, so the cheaper the better while still being able to tell me if my fiber is good enough for 10Gbit.

thanks.