I get the cheapest halogens I can find, then disassemble the mounting arm a bit. Most have these adjustable arms that have a hole in them (to mount to a base). I remove the base and that leaves you with a hole to mount to a tree, fencepost, etc.
The black part on the bottom is the arm I'm talking about. The base (yellow part) I just toss. It looks like the one in this picture has 2-3 holes to use.
I'm Joe from Backyard-Hockey.com and EliteRinks.com.
Please visit your "User Control Panel" and update your location, rink dimensions, and materials used. It helps us when giving advice.
Oh, and check out our new book -