I remember umming and arring in '76 when prices went up from £7 an hour to £9 an hour at my local school (they had a Tiger Moth as well at no extra cost....). I decided that gliding was cheaper..........
Mind you it's all about relative costs etc. I think I was earning about £200 a month back then so four hours a month would have been around 18% of my monthly earnings whereas if I fly for four hours a month now it's a lot less than that.