Definitely check Ebay. I got a sweet collection of bamboo needles at a great discount (about $4/pair including shipping). 36 pairs total, 12 each in straight, DPN, and circs in sizes 2-11. I had a few pairs of aluminum needles in mid-range sizes (6-13). Love the bamboo needles!
Eventually I'll invest in the Denises. It just makes sense to me to have a compact, versatile set like them or the Boyes.
Other places to find needles are Goodwill and yard/estate sales. You really don't have to spend a fortune to get a decent set! Keep looking, and take your time. :D