I use the combination of callcentric's free DID ( you get only an area code from NYC) and the 911 service- $ 1.50 set up and $ 1.50/month. Free incoming calls, outgoing calls attheir regular rates pay by minute.
For business use I would choose from their web site depending on the expected use. You may also want to take an additional provider like Google Voice or Localphone for calls which are a bit less important .