Let loose with crayons if possible. Or footprint card if not. Get them in the high chair, paint on foot, foot on page, wipe the foot. Can try finger painting if they are good at not eating whatever toys. Saltdough clay footprint ornament. I'm not going to fall into a trap of spending actual money on behalf of someone who brings in no household income 😅 our money costing gifts from us will also be from him 😀 As a cheap one that does cost something I think nice ideas are a framed photo or album, photo keyring, I got my mum a photo notebook (from me) and my dad a wall calendar, snapfish has a deal on calendars.
We did a Christmas bauble with handprints on. Agree with Alex snapfish is fab!
For my partners nan last year we brought her a frame from the kids and now we update those photos every year as they grow so quickly Or something personal to them like a photo pillow A nan and grandad plaque etc