My wife (who was buried this summer, and passed at age 30 of cancer) was buried in a simple stainless steel urn in a small country cemetary. The most expensive parts of her burial were her funeral, and her tombstone, and combined they cost about $5K. (I went with a highly polished black tombstone, because the lettering is easy to see on black and if it were polished it would withstand the elements a bit better.)

On the flip side, I kept some of her ashes and recently buried a bit under a tree dedicated to her where she worked. I haven't decided what to do with the remainder of her ashes... We'll see.