Least expensive : I made my own and it cost me about $4 for the light at pepboys.
Less expensive: I copied an aluminum one that sells on Ebay for about $10 + shipping (no light included)
Most expensive: Fancy billet one with LED'$$$ I see that you are in Surprise, I think Everything offroad around the 101 & Glendale has one, and I think IF motorsports on Bell Rd around 43rd ave, sells the same one.
To tell you the truth all the shops I have seen sell the same stuff, Plate holders, billet mirrors, cup holders, name plates etc... (in my opinion it's all overpriced :)
If your asking about my mirror ?
It's just the 5 panel mirror from Pepboys (checker has them to, I imagine autozone carries them also)
$20 everywhere O0
To mount it I drilled into the roll cage with a small drill bit and then used a couple self tapping metel screws to secure it. It works great, and because of the wide view you really dont need side mirrors.
However if you look closly you can see my little "blind spot" mirrors on the vertical bars of the roll cage.
They work for what they were ment for "Blind spots". but the main reason I have them is they let me see whats going on behind us when my daughter is driving .
The 3 panel "billet" mirrors run around $165.
IMO they really dont work that well. they are too skinny and short.