Grass Autotests are a great cheap way into motor sport. You do not require a competition licence and the car can even be an MOT failure as long as its not dangerous. Basically as long as nothing is hanging off and the brakes work you're on your way!
A helmet is not necessary (although recommended for juniors). The events are not high speed. The circuits are tight and twisty between closely spaced cones so you will be running in first or second gear throughout. Cars can be double entered so you can save costs further by sharing a car.
Vehicles need not be registered or taxed but they must comply with basic MSA technical regulations i.e. battery and seat must be firmly fixed in position, no bits should be falling off or loose, there should be no fluid leaks. Cars are scrutineered before each event.
There will be awards given out on the day to all class winners. The results count towards the club championship, with a trophy for each class winner at the year-end as well as an overall champion.
You can start from as young as 14 in the production class but you need to have an adult with a driving licence in the passenger seat. The car needs to be less than 1400cc.
Regulations can be downloaded here