DH is being best man for his mate.
The other best man (oh yes, can't just have one) and the groom have organised the stag do - it is going to cost a mere £200 if he sticks to a tight food/drink budget, and that doesn't include the petrol costs to get there.
All of them (apart from DH) work in well paid computer jobs with no families to support/commitments etc.
For us, that is more than the food budget for a month. We scrape by every month as it is.
I can't just say "You can't go", but at the same time I am worried sick. I have no idea how we would raise £200 and even if we did have some magical way - there are a hell of a lot better things to spend it on than one outing. He is worrying too, but can't see a way out of it.