I would guess the average price of an ornament on our large tree is $5-$6. The tree also has handmade ornaments and old heirlooms that were on my parents and grandparents tree so it's really quite an eccletic mix. On our first tree we had a box of glass ornaments we bought in Sears (quite inexpensive), some gifts and a few Hallmarks that we bought that season but we also had styrofoam balls wrapped in metallic colored paper that we made, (Very cheap and we still use them.) There are also some gift ornaments that we recieved over the years from generous friends and family that probably cost considerably more that they thought we should have on our tree.
Another tree that stands in the corner of the dining room is exclusively decorated with traditional german ornaments-some wooden but most handmade blown glass. I have a thing for these and have been collecting them buying a few each year. They tend to be pricey-some were under $10 and two were over $60 (however I got these at a summer sidewalk sale at a wonderful little Christmas shop in New England for less than half of the original price). I vew these as collectable art as much as ornaments so it is really a hobby that I get to display at Christmastime.
I guess the bottom line is that if an ornament makes you feel happy and you can afford it at the time you're probably going to buy it.
"Christmas stays if we don't forget its meaning"