How do I Figure Out Which Wifi is on a Flight and the Pricing?
 

I see on the Virgin America website that there are two possible wifi providers (ViaSat and Gogo) and that the price can range between $4.95 and $39.95 (https://www.virginamerica.com/cms/vx-fees)

Is there any way I can find out before a flight which wifi provider services the flight and the actual cost?

Unless you are flying to/from Hawaii, there's about a 99% chance that it'll be Gogo.

You need really to track the route and the plane by tail number on Flightaware or similar to know which has ViaSat or Gogo. Maybe 4-6 of the 60ish planes in the fleet have ViaSat, which is awesome. ^

I don't think you can tell prior to being on the plane itself. As I understand it, and once you're on the plane, if the WiFi network is labeled as "Virgin America," it will be ViaSat. Gogo is labeled as such.

Last month, had gogo on IAD-LAX.
Had an unused gogo-inflight, so was able to take advantage of that outbound.
Bought a gogo-inflight at LAX before boarding the return flight.
But on the way back, it was the new in-house version. Better performance, but I have another unused gogo-inflight.

Unfortunately you won't be able to tell more than a couple days out and even then it's not set in stone due to possible tail swaps. If you are able to find out what Aircraft is planned to operate your flight (I believe it is Flightradar24 that has been fairly accurate) you can find out what wifi you will have. Aircraft with the registration N2XX and N3XX have viasat while those registered N5XX,N6XX, and N8XX have gogo.