http://greenpowerscience.com/ This is a very simple trough design you can run a 100′ trough for less than $500.
It is always best to install your solar panels where they will get the most sunlight each day. It is important to check regularly for trees that may be overshadowing solar panels due to growth.
Low prices can be very attractive but keep in mind that solar panels and their installation is not cheap. If a vendor has extremely low prices, you are probably getting low quality equipment or even second hand equipment. It is best to invest in quality solar panels and hire a trustworthy contractor to install them.