Is it possible to start 1 man company (for contracting) and still get 30% ruling?
To qualify for the ruling you must be an incoming employee. This means that you must be employed by a company and have an employment contract (arranged before you come to the Netherlands).
A freelancer is not an employee but self employed. Consequence is that the 30% ruling is not applicable. This will only be different if you work through your own limited company (either a foreign Ltd which must be registered in the Netherlands or a limited company which is newly set up in the Netherlands) or if you work through a contracting agency/payroll company. In that case you will be employed, although the tax authorities could argue that you should be employed by your client directly if he is your only client and you therefore depend on him entirely (only applicable if you work through your own limited company). The contract with your client will have to be set up properly to prevent this and a so called VAR must be requested.
Expatax can assist you with:
the registration of a foreign limited company