Hello,
I started to search for all the brands for ongrid inverters and created a spreadsheet sorted by price/watt.
I hope all of you can contribute to it so we'll know what is the cheapest product. I found the lowest price/watt to be 0.18$ . Lets see if we can find anything lower... Check my table here and post your findings so I can update it.
http://ongridmaster.blogspot.ro/p/brand-model-power-watts-price-watt.html
This is not a commercial link and I'm sorry if I'm not allowed to post URLs.
Thank you,
OnGrid Master