You will need to be able to perform simple maths calculations. Difficult one to answer. However, there are lots of people flying that are not earning large sums of money. You can get in the air in a wide range of craft including gliders, microlights, gyrocopters and light aircraft. Typical PPL training costs in the UK are between 80-110 per hour.
Most flying schools offer discounts when hours are block booked.
Additional savings are often offered when a 40 hour package course is pre-paid. Many people turn to the USA and South Africa for training packages. These often offer substantial saving but make sure you read the small print. PPL courses will vary in the number of lessons and amount of flying time according to your skills and a number of other influencing factors such as weather, traffic, aircraft availability, work and family commitments etc. but would typically follow similar lines. The sample below is only a guide but gives some idea of nature of each flying lesson and the structure of the course.