Dan,
PV panels were about 3.50/W in 2011 and dropped to below 1/W in 2012. If the cost stays that low is a question though. Several large purchasers of the PV panels such as Germany, Spain, Italy and I think also Australia cancelled the subsidy in 2012. In the same time China put on line the largest silicon wafer plant on the world. So there was a glut of the PV panels on the world market. Well that is the story I heard.
We financed the system by a home equity loan. I figured that at current interest rates it made a sense because the interest (in addition to being low) is also tax deductible.
If you have new metering that DIY system will pay for itself in about 6-7 years.
I got my stuff at Civic Solar.
CivicSolar | Solar Panels - Photovoltaic Cells - Solar Power - Inverter - Charge Controller - Battery
I paid $225 for 250 W Canadian Solar panels, 135 for 215 W Enphase microinverter, 23 per a section of Enphase cable and estimated another 180 for associated hardware such as solar rails, wood, concrete, bolts, breaker boxes, disconnect and 500 ft of cable to transformer etc. That is about 2.25/W or $562/panel installed on ground before tax rebate.