If you are operating public transport, you will need an AOC so most people will "rent" one from an established operator.
For a King Air you could talk to Titan, GAMA etc...
Going solo will require you to get an approval from the CAA, which without any experience in the business, you are unlikely to get. i.e you need a Chief pilot, a quality control manager and other JAR requirements.
Buying the plane is cheap so it is by far the easiest step to take.
Also remember that a turbine A/C seems like a relatively affordable option until you start paying
- Euro Charges
- Landing/handling fees
-Normal maintenance
-Unexpected maintenance
-Insurance (don't know how much experience you have but operating PT might require you to employ a more qualified (insurance accepted) pilot.
Saying that,if you can do all that I will be a little envious since that would have been one of my dreams.
Maybe later....
Good luck