This plastic bottle cage weighs only 35g, saving up to 24g over a generic alloy cage, or 48g per pair. They resemble Elite Custom Race cages, and while not as stiff due to not using glass fiber, offer the easy insertion and removal of cages like the originals. Unlike the aluminum cage, it will not mark up your bottles as much either. At $5 for two, and saving 9.6g per dollar, it represents an exceptional value, very low cost upgrade. It can be purchased on eBay.
Price: $5/pair [Very Low Cost]
Value: 9.6g/$ ($0.10/g) [Exceptional Value]
Recommended with caveats
This is heavier than the other cages, but offers easy insertion and removal.