I'd love one too!
The whole chipping-in thing has been pretty normal at the last 2 places I've worked at (one public sector, one private sector), but I know what you mean - I don't think my DH does it very often. They're more likely to go out for a drink or two after work to celebrate (although shouting a round of beers probably ends up being more expensive than chipping in $5 for a pressie lol).