No ideas as such but I sympathise.
My DD is nearly 4 and her dad's side of the family are very materialistic and always go over the top.
For example, her Granny doesn't really have a relationship with DD because she doesn't make an effort (even when she's here) so what she does is ring up lots before she's due to see her and go on and on about the presents she's bought DD.
It got to the point where DD was constantly asking to go and get presents at Granny's.
. Like you said it was mostly useless plastic tat that I'd end up sweeping into the bin broken etc in a couple of weeks/months.
I've banned the talking about presents now and talk about seeing granny instead and have said only one small thing/chocolate as she used to feed her twice the adult daily allowance of chocolate plus cakes and no 'proper' food every visit too (her son is obese, surprise, surprise) and we'd get the same whinging about chocolate for days afterwards.
I've banned watching channels with adverts in the morning (only cbeebies allowed) and made DD participate in a toy cull before Christmas this year explaining that some children have nothing.
I also try not to use 'taking things away' as a discipline as I think that just reinforces the 'importance' of things.
Aside from all that, I do remember writing down very long Christmas lists I clouding the Argos catalogue page/number every year but never got those things and looking back at my school diary, aged about 7 my favourite present was a 'Make mosaics' book! I'm not materialistic in the slightest now. :)