HOAs won't give out money, but cities give out rebates for people to take out their turf and put in xeriscape.  I don't know what the current amount that Aurora gives out, but in the past it was substantial.  Not to mention they hold free classes for people that want to put in xeriscape.

BTW, for those HOAs that have all sorts of rules about how much lawn coverage people have to have, tell them to pack sand.  Colorado law specifically states that HOAs can neither prohibit or restrict xeriscaping.