To the best of my knowledge, this class of engines were originally developed for model aircraft.
But certainly not cheap, looking around $2,000 mark and much of that would be due to supply/demand aspect. If demand increased, that price would drop.
Coming soon to a wannabe State Level Actor's arsenal! I'm thinking Da'esh here, but could equally well be white supremacist militias or the New IRA post-Brexit, or just about anyone with a weapons R&D budget in low single-digit millions.
Just as smartphones have given us all a general purpose James Bond gadget in our pocket, so too is the availability of cheap computing elements, drone components, and tech like this going to give every militia on the planet the sort of smart weapons capability that was bleeding edge in the 1990s.
https://www.youtube.com/watch?v=u42QrTqmYwg
The description of the video contains all the numbers, including:
Max. power: 300N (30,5kg)
Fuel consumption: 980ml/min (at max power)
Price: 5295 €Some of the earlier attempts did have ballistic parachutes but you still had to deploy at least 75 feet high. Any lower and you're dead.