Here is a break down of the cost. Keep in mind I really didn't do too much "bargain shopping " so you can probably make this cheaper than I did.
5 LEDs
-2x Cree 3w XPE Royal Blue $12 ea
-2x Cree 3w XPG Cool White $12 ea
-1x ProLight High Power 3w UV $9
2 Drivers
1x 1000mA Constant Current Output, External Dimming w/ pot. $20
1x 700mA Constant Current Output, External Dimming w/ pot. $20
Power supply
1x 24v 6.5A Potrans $24
Heatsink
7.280" Wide x 6" Long Heatsink $15
Wire,solder, ect. ~$15
So altogether Its around $150 give or take, again you can probably find the material cheaper than I did