What to buy:
I collect Nativity scenes, and the ones from South and Central America appeal to me particularly. I found my Mexican one in Oaxaca. The choice was huge, themed in every colour imaginable, but I liked this little rustic one - its natural colours and naive charm were more to my taste than the rich reds, purlpes, emerald greens, etc of others I saw.
I also found Christmas tree balls - not of glass but woven grass, another Oaxacan craft.
What to pay: The Nativities are priced according to how many pieces make up the scene - some have an enormous number of characters. There's one for every budget.
My straw balls were less than $1 each.