Well assuming you do have some spare money but not so much that you can spend on anything you want with no thought or compromise, you have to prioritise because the more you spend on Christmas, the less you have to spend on other non essentials.
Ideally, you'd review all your budget to maximise your income, account for your essential costs and check these are all at the best price.
Then you need to account or annual and irregular essential costs like insurance, car repairs, servicing etc, school shoes/uniforms etc and so you have some money available should the washing machine etc break.
Note that we haven't thought about Christmas yet because all the above is more important.
You'd also want to think about making sure your pensions are on track and that you have emergency money should you lose an income.
Once you've dealt with all the above, you'll know what you have for non essentials, which needs to cover Christmas, but also days out, grooming beyond basic haircuts, coffees/meals out etc, holidays, hobbies, sports etc.
So you need to split the money available for all these sorts of things according to what's important to your family.
If you want to spend a lot on Christmas, you'll have to spend less on other things. But in any case, you need to save money each month to pay for it. But as for what you buy, think carefully about what's necessary. Many people buy far far too much and most of it isn't wanted by the recipients.
Martin Lewis has been trying to persuade people to not overspend or get into debt for Christmas and judging by all the crap in the shops, pictures of giant piles of gifts on social media and threads on here stressing about buying for people who've said they don't want anything he's not really succeeding. But lots of budgeting advice here:
https://blog.moneysavingexpert.com/2018/12/martin-lewis--how-to-go-christmas-cold-turkey/ In short, save what you can afford and use that money to have the best Christmas you can without overspending.
We don't have DC and don't spend very much, so don't budget as such. But things like decorations and wrapping paper are always bought in the sale the previous year. I don't think I've ever paid full price for these things and most of our Christmas decorations are the original set I bought nearly 30 years ago, with just a few added on over the years when I've seen nice ones reduced.