As others have noted this year, I've gone over budget but feel like just a year or 2 ago, £250 would have been a very generous budget and covered all gifts and extras.
I aimed to spend £300 per child (I save throughout the year, we don't buy too much through the year, and we don't do loads of presents on birthdays as the focus is more on a treat day), but have gone over by about £50 each for the older 2, and slightly over for my youngest (mine are 9, 7 and nearly 5).
It's not split evenly between stockings and tree gifts, as my DD loves a stocking, and as she gets older her gifts are smaller in size so fit nicely in a stocking- though our stockings are big and more akin to Santa sacks than stockings that just fit a few chocolates in.
I'm honestly surprised how much I spent on my youngest, he is usually the money saver, but he's great and I've found some really cool stuff for him. His brother was never really into toys in the same way, so we don't have a lot of hand me down toys from older siblings, and they have all got new interests so really needed some new stuff this year.
With my oldest, I could just keep going this year tbh. But we've spent that money and there are no huge big expenses, no consoles or tech or anything. It just adds up far too quickly!
I've still to buy those last bits, I want to get my son some Vbucks and possibly a lego set, and my daughter a few bits too, possibly some trainers and a couple of bits I have missed off her wish list, like a cute diary and a specific book.