The club where I'm an FI do charge an extra (optional) £5 for a certificate and photo (6"x4" framed) on top of the £130 for a hour flight. If somebody did want just the certificate I suspect we'd give them one for free, bit of A4 with some ink isn't exactly expensive. Better to send the customer away happy and enthusiastic, than make an extra couple of quid, but never see them or any of their friends again.