I bought some cheap ASDA primer last night. Popped some on eyelids this morning before eye shadow and have been out until now. Been outside (cold, wet and windy west of Scotland) in a country park and been in a meerkat enclosure with them literally climbing all over us. And eye shadow is still on.
I am 31 on Saturday and have never used primer before - so I thought I would recommend it to anyone else who was thinking it is a waste of money. I think will actually save money - less reapplying eye shadow!