How old is G? There are a lot of little things that kids get a kick out of. A tub of playdoh was in a party bag after a party we went to last weekend and the kids loved that. Or a plain Christmas bauble that you could use a glitter glue pen to write G's name on - sort of a thoughtful pressie for him to have his own special bauble to put up on his tree (if you've got neat writing!). And if you bought a pack of baubles as I figure you usually have to, then you'd have some spare to do for any other little pressies.
Not sure about the other pressies. Do they go all out on their Christmas decorations? If they do, maybe you could find some nice Christmas deccies they could add to their tree... or is that just lame? And as for being tasteful but not expensive... if that IS an idea you'd consider, maybe you could do it for next year instead.. wait for the after xmas sales this year and then buy them something nice (yet on sale) for next xmas

. Okay I'm out of ideas

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