Q) How do you make a small fortune in aviation?
A) Start with a large one!
1) Not in the way you're suggesting.
2) Depends whether the airfield operator also offers training, in which case you probably wouldn't be welcomed, or they see you as a tenant who's going to have to pay them hangarage / landing / parking no matter how good or bad your business is.
3) Basically yes, but factor in the costs above and you'll probably have 50p to live on from your £100.
4) Not normally - how do you think they make their money?