Birthday and Christmas presents, how much do you spend on your children?

It's our son's third birthday in November and of course Christmas the following month, I have bought a few things over the year in sales (mainly ELC) but it doesn't really look or cost that much.  I don't want to buy too many little bits and pieces, and would rather buy something that will last and be played with rather than hide in a cupboard and get forgotten about, but he is at the age where they love opening things.

Also I think there is pressure of a sort when people ask what you getting them, after listening to how much they are spending on their children, even at this young age. 

I have been looking on eBay this week at Duplo sets for Alex as he really likes the set he had last year, and I have been wondering whether to try and get some fire station or police station sets on there, but I have my doubts. I feel a bit weird buying second hand things for a present, but don't really know why, as you can get so much more for your money and something like Duplo always looks in good condition. 

So just wondering, how much do you usually spend on your children on their Birthday/Christmas presents? Have you ever saved money by buying things second hand for a present?

I'd love to hear your thoughts and opinions.