Virgin 'anything' oil will be expensive for Biodiesel. I used to use biodiesel exclusively. I drove almost 2 years using > 20 gallons of regular diesel. I bought the biodiesel in bulk from a local producer who ws making it from waste oil. With the subsidy it was usually about the same price as diesel. I bought fuel in bulk (200 gallon sat a time) which would 'fix' my fuel cost for however long it took me to burn 200 gallons of fuel. At 40+ MPG, it took a while :).
I stopped using biodiesel after a diesel fill rendered my car un-drivable due to the injection pump leaking so bad. I sent the pump out for re-seal and it ended up costing $1000ish to repair the injection pump due to corrosion inside. The Root cause was deemed to be water in the biofuel.
Once fixed, I haven't touched the special sauce. In general I'm not sorry I tried it, but it did seem to cause or as least exacerbate an injection pump issue, it got about 5% worse fuel economy, and seemed to make slightly less power. On the plus side, it usually smelled like Chinese food vs diesel exhaust stink.
I still have the car but has since sold my home Biodiesel fuel station.