£90 for an intro flight seems a bit steep, it's £30 at my site which includes a months membership. Once you join a club it's not expensive. My club is £190 a year membership and £6 for a winch launch. Soaring in a club glider is 30p a minute, so basically an hours gliding costs £24. Of course if you have your own or a share in a glider you just pay £6 for the launch and fly all day if you want.