Buffy rarely got out of Sunnydale?.

Lots of schools finance charity trips. Same with churches (though we get no indication Buffy is religious). It' uncommon that a girl spends 3 years in high school and only ever leaves to visit LA where her BF (more or less) is, and where she first came from if I remember correctly.

And Buffy/Joyce never struck me as anything but solid to upper middle class. They have nice house, Joyce works part time, they never seem to be struggling for food or funds while Joyce is alive, providing for three (after dawn). Buffy's dad clearly is dong alright being in Europe living the cliche, and no doubt he pays alimony too. She wears nice clothes, does not work, enjoys the club...she ain't destitute. Nor is willow. Now, Xander we see evidence of a lower middle class to possibly even near impoverished. He has a crappy car, has to live in is parents basement, he complains of the cost of rentals, costumes, etc. From him, we get the idea money is tight, so I can absolutely see his lack of world travel.

Say, do you hear that? It's the sound of the Reaper.....