The concept is really good - promotions and admission fees increasing modifiers makes a lot of sense. The art is nice too - I love the little rocket man in the stall!
My suggestion for improvement would be to change the currency/ multipliers so that it is limited to two decimal places. That way it makes sense as £GBP, as you cannot have 0.001 of a pound, for example.
Other than that, solid game! Good job.