Sorry for reviving an old thread but have some info that might be helpful.
I built my own led panels for cheap. They are just as effective as commercially sold ones, maybe a bit less efficient, but cost 10x less.
Firstly, the internal components of the assembly are dirt cheap. Do some research on how to assemble these cheap components and you will find in the end that you have a system almost as good as a store bought LED panel.
This is how I started off:
54W 6500K LED. $2.90
54W constant current driver. $8
CPU heat sink with fan: $12
Housing built from scrap metal that probably doesn't even cost $2.
That's $25 for a 54W fixture. Commercial sellers have prices ranging from $1-3/Watt; this is 4x less.
All items purchased from alibaba, eBay, Aliexpress.
Next system I'm building now is like this:
500W constant current driver. $110
10x 54W 6500K LED chips. $29
Aluminum panel with 4 CPU heat sinks and 2x fans on each end (1 inflow, 1 outflow). ~$60.
Total cost: $199, for ~500W system. If I wanted, I could've also used blue red combos (these chips cost like $1 more).
You wont find a 500W LED system on the market that costs less than $500. I built mine for less than half that price, tailored to my needs.
My next system that I'm still planning removes the entire conventional cooling system of heat sinks and fans. Instead, cooling is provided by chemical reactions (i.e. sublimation of dry ice). Still working on the idea.