Another option is to look at these "import" or "surplus" stores that usually have a little of everything. I found some beautiful Russian etched glass ornaments for next to nothing at one of those stores.
Also, remember: less is more. A tree covered in ornaments looks like just that. But if you use fewer ornaments, you can buy better ornaments. Also, use clear or white frosted mini-bulbs for a nice, elegant lighting scheme. We have some Crayola white frosted bulbs that look really nice.
Also, stay strictly away from tinsel and icicles. It's not elegant. Yes, it does add "sparkle" but not elegance. Plus, icicles are the very devil to vacuum out of the carpet -- much worse than pine needles.