Don't worry about what other people do. It is beyond crass to publish all these 'look at flossie's massive pile' photos - I know people who do it for birthdays too. Big pile of pressies, helium balloons and banners draped across 'ready for X in the morning'.
We have 4dc so splurging in that way is never going to be an option. They have small stockings, one gift from their Santa list and one thing from us that they really want. £shops are a great resource for a bumper pack of wax crayons. That and a roll of lining paper, happy child scribbling away. Especially if you draw round them. Look on Pinterest for 'diy' gift ideas. Guaranteed you will have things in the house that you've never thought could be repurposed.
This year in our house has been awful for the 'I want that'. They're watching far too much nick jnr TV with adverts. But at 7, 5, 3 & 3, it is to be expected. We'll just be managing the demands with they can't have everything they want and if they're desperate, they can save for it.
Your son is so much younger so enjoy the lack of demand while you still can. And enjoy a lovely Xmas with the 2 of you. I suspect you're feeling down more than usual because of being alone as well.
Making memories with decorating the tree, paper chains (happy childhood memories for me), spending time not money. Those are things which kids remember. Not who bought the biggest/most presents.