Good insurance cover

[Arfa]

But what is the total cost for being IAM

Initial course costs £150, but 10% vouchers are two-a-penny, and it is often down to £100 for those at sign up at various shows.
Yearly costs are about £45 (£30 ish to IAM HQ, £15 to local group).
So yeah, do your sums to see if the saving outway the costs. But obviously you get a lot of other stuff too: skills, a social scene, ride outs, other discounts etc. And, as has been said, they're not always cheaper on insurance for everyone. For me they have been for last 4 years odd, but I know others in my same group who didn't find them cheaper.