The RR250-C20 that delivers around 400 shp and is standard in most lighter helicopters burns around 26gph. It is not impossible to assume that a smaller turboprop in the 100-150shp range could get to around 10-13gph at low altitudes. Up high, that figure will drop with a bout 50% to around 7-10gph, I'm guessing. Granted, this is more than a piston engine, but still pretty competitive considering the price difference of Jet A1 and Avgas in Europe. Not to mention the availability.
Price difference in the US is almost non-existent, so therefore the incitement might be less. Availability of Avgas is also much better, but that's going to change.