Here thats certainly customary, but its not necessarily a situation down “meal” for adults.

I went to a 3 year olds party a few weeks ago. At a kind of cafe that had a playground.

The food laid out was just sausage rolls and little pizzas and things like that.

You could order coffee and juice and that was paid for by the hosts. If you wanted to order a meal you would’ve had to pay for that.

Myself and my 2 kids attended, and we gave the birthday kid a book, and enough money in a card to cover the cost for the 3 of us.

YMMV with the cash gifts, but when our little darlings were 1 we put on a party in a park and made a tidy profit. Lots of work though.