Owning a private jet is expensive, and the maintenance will kill you.
You might want to consider fractional ownership or renting.
Well , it is really depends on what is the size of it and what features you want it to have internally. The variety is huge, and so is the price range
A new jet will be between 10 to 100 million, but an older one might be less then 10.
So, in order to answer it- we need more details