UK Car Repair: Aux drive belt, serpentine belt, approximate price

Question
I have been told that I have lots of cracks in the aux belt, what is this and should I get it sorted ASAP?

Thanks

Answer
That's fanbelt or serpentine belt - It's a normal service Item(consumable), cracks in the rubber indicate it is old and at the end of its reliable service life.

What is the make, model, year and engine size, diesel/petrol, trim level (eg, GLE, SRi, GT, GLSI)

Then I can give you an approximate price for the belt since prices vary enourmously
That said I have changed a fanbelt for £10... so not expensive.

If you can tell me the vehicle details and what country you're in + approx location and I can source you a cheap belt and honest garage.