Presents only for people still in full time education.
Presents could be a nice version of something the recipient needs.
Lighting up fairy lights will barely be noticeable on your power bill.
Join in local events - brass band round the Christmas tree, Father Christmas at a local school, am dram panto rather than spending significant amounts of cash on professional versions.
Charity shops often have lots of decorations
"Christmas jumper day" at school - pin tinsel, decorations etc onto an existing jumper, or sew on cut out felt shapes.
If you have a decent size freezer, buy yellow stickered meat, veg etc in advance and freeze it - blanch the veg and then cook as normal. Instant custard is just as good as cream on puddings and much cheaper. My dc prefer frozen apple strudel, which is about £1.50 from Lidl to Christmas pud.
13 years ago dd was a few weeks old and dh was made redundant 5 weeks before Christmas. We'd already bought ds's (3) present, so all we really "needed" was food and we chanced it on yellow stickers as the shops closed on Christmas Eve - it worked out fine! We had salmon steaks (half price) instead of meat, and lots of veg for a few pence. All sorts of random bakery bits. A big cheese platter!