For most people, a Learjet model will do the job.  This jet is like an oversized SUV - big enough for your family and a few friends to take that trip to the beach and avoid the traffic on Friday evening.  Plus, you don't have to rush home on Sunday evening and again get stuck in the traffic.  You can simply fly back on Monday morning and still be at work.  It will run you in the neighborhood of $10 million but this can go down significantly if you buy a used jet or you select fractional ownership (more on that later).

If you are truly the jet-set type and want to do business while on the plane or want to let your business associates and employees use it, expect to spend about $40 million (these models are made by Boeing, Cessna, Gulfstream, etc.) but we will not get into the details here since it is often a business decision (buy/lease/charter).  It may be pointed out, though, that if your business needs to fly small groups of people almost on a daily basis, most cost-benefit analyses show that a private jet turns out to be cheaper than flying business class.

If you understand the concept of timeshare, you know exactly how fractional ownership of a private jet makes it affordable.  Since it is unlikely that you will be using your jet as you use your car, it is best to let others use it while you are sitting in a dull and boring office all day.  Which means that with all the other options like financing, you can actually "own" a private jet for essentially few thousand dollars a month.

What else to consider when buying a private jet?

• Like a car or a home, you will need to carry insurance and pay for maintenance.
• If you don't have a pilot's license, you will need to pay a pilot.  With all the layoffs in the airline industry, pilots are desperately looking for work but many of them still like to get paid a lot of money.  So negotiate hard; the airline industry in the US is basically headed south.  I expect a lot more layoffs and consolidation in the industry, both of which mean more laid off pilots who will be willing to work for a lot less (while you and I can do lots of things, these poor pilots know only one thing and have no transferable skills at all).
• Do your research online first.  Even check out eBay.  Get smart about jets (particularly if you do not have a pilot's license and know only little about planes).  
• Look on the Internet for trade shows and exhibitions.  Attend one or two of them to see new models and check out the prices.
• Avoid a dealer if you can.  Buy directly from the manufacturer.  They will be happier to serve you.

Related link: Life of a flight attendant    Airline credit cards