northern boy,
just because it has been over five years since a rating has lapsed there is no need to spend a fortune revalidating. The requirement to revalidate is "retraining at the descretion of the TRTO". I myself renewed a type rating a few years ago. It had been lapsed for eight years after having flown 3000 hours on the type. I had since flown about 5000 hours on two more types. I renewed it with a writen test on systems, and an LST.
For a 737 I would expect this should cost a couple of grand.