Depending on what type of Solar business you are into, you can either buy them directly from solar lead gen networks/publishers or you can generate them by running ads.
If you are Solar business owner, who wants appointment set up, then find publisher or post your offer with networks to generate appointment for you. Prices will depend on how much details you need in a lead to the Zip you are targeting.
If you are just looking to purchase them to do cold email marketing or run through call center, then you can just go to lead sellers and get them for cheap as pricing would depend on real-time and aged.
Do a google search for Solar Aged Leads and you will see lots of options. I can remember two networks right now which used to work on solar campaigns, you can check with them. Look for PX and RPG or RMG Media in USA. These are just suggestions and do your due diligence before purchasing leads from anyone.
