gps is the cheapest replacement speedometer there is
I've had two vehicles in the past where the speedometer decided to stop working. Each time it was well over $100 to fix - and bear in mind this was over 5 years ago. On one of the vehicles I had to custom order a gauge cluster, and for the other the cluster was in stock in the shop.
If I had a speedometer bust today I wouldn't even bother replacing it. Instead I would purposely buy a Garmin nuvi, use double-sided Velcro and stick it right over the busted speedometer.
