Exactly Newmum. I don't know how the OP, and half the thread have interpretted 'a scratchcard or two' as needing to be £30 worth.
I would probably spend a tenner on scratchcards, getting a £5 one and then a fiver's worth of £1/2 ones, hopefully choosing designs that are relevant to the Bride and Groom in some way.
They don't have to scratch them all off straight away either, they could just do a few each day as part of a relaxing evening, taking into account any expiry dates of course.
They're bound to win off a few. I buy a couple of scratchcards a month and win about 1 in 3 or so. If it's a win of a couple of quid or up to about a fiver, I get new cards, as I only ever buy the £1 ones, so will use the win to try out a more expensive one. The time I won £20, I kept that, rather than cashing it in.
I know that some poorer people spend a disproportionate amount of their income on scratchcards, but you can say that about all vices - alcohol, tobacco etc.
If the B&G had asked for a bottle of fizz, whether Aldi cava or vintage champagne, ie of the givers chosen budget, would all the misery guts be wittering on about alcoholism?