I learnt to fly at Moray Flying Club based at RAF Kinloss almost 10 years ago. You won't find any cheaper than this because it is not for profit and fuel is subsidised by the MOD. It's also a very interesting place to learn to fly and the instructors were great when I was there. They allow a number of civilians to join to bolster flying hours.
But frankly it depends on where you live. Scotland is quite a big place and transport links aren't great. Having said that I drove from the Aberdeen area 1.5 hours for every lesson.