Amazon has a 5w LED Landscape Spotlight [amazon.com]
on sale for $8.49 when you apply coupon code LVVH3ITN
Alternatively, the 10w spotlight is $16.98 with the same coupon code (LVVH3ITN
These lights are adjustable and waterproof. They can be installed in the ground, or hung. They are made of die-cast aluminum and glass to protect against corrosion. They are both waterproof.
The lights both come with a two-year warranty.