The donation of a voucher for X pounds off a course. This still means you have to spend at least Y on the course and in this instance Y is a lot more (at least double) X. Either way, it isn't a prize by my definition and what it is is free advertising for the woman running the course.
Or have I got it all wrong?
Woud you include this in a raffle?
(don't want to give details of donation so am being as vague as possible).