How much to get a car undersealed?

[bobuk]

The easy bit is slapping it on.
The more time consuming bit is suitably cleaning under the car such that you’re painting the car and not rubbish and grime.
Had my MX5 done for £350, including that clean

Undersealing an old car. clean and grind off the rust takes a lot of time if you dont do thid you will seal the rust under the underdeal so it continues to rust and you don't see it, wax oil is proberly a better bet.