We don't have a budget per se but the DC are all still quite young so no big ticket tech or fashion items are being requested - yet. We'll be imposing a budget once they start asking for £100 trainers etc.
All 3 of our kids have birthdays within a month of Xmas so we have to do Birthday and Xmas gifts. Automatically our costs will always be higher.
All 3 kids have asked for lego advent calendars this year so they know this means they wont get as much spent on presents.
We don't do Xmas Eve boxes or any big events, but the past few years I've managed to book tickets for the Sky Garden in the week before Xmas so we go there, have a walk past Tower of London and across Tower Bridge, check out the winter market on South Bank and then have dinner somewhere (usually just a chain)
We only do gifts for parents as we both have massive families (I'm one of 4 and DP is one of 6, we have 20 neices and nephews!!) Thankfully siblings on both sides all agree - we do kids birthdays and first Christmases but Christmas gifts for so many people is just too much!
We take treats if we meet up with / visit any of our siblings and kids over the festive period but there are no actual gifts.
We use Nectar points for all the Xmas food and booze (although I dont drink and DP rarely drinks so it's usually just a few bottles of wine to take round to people / to open if we have people over)
We save all our silver and £1 coins over the year and count / bank them in December - this pays for the Christmas tree and any miscellaneous stuff we need to buy. We bought some beautiful and very expensive tree decorations the first Christmas we lived together, 18 years ago now and have added pieces over the years / replaced lights etc but we essentially have the same decorations every year on the main tree.
We aren't well off but don't have to budget strictly. However I'm mindful we have to do birthdays as well as Christmas!!