The first thing would be to find out if an inexpensive scanner will work in your friend's area. An inexpensive one is pointless if the only traffic in the area is trunked digital that a cheap analog scanner can't decode.
City, County, and State would be needed information to determine the proper scanner.
Also, which agencies would he want to monitor?
Once those questions are answered, the opinions will be plentiful - along with which antenna would be best for the application. Which brings up another question, are there any restrictions in the development where he lives? How about rural or more urban location? Is it open, or are there a bunch of buildings around? First floor, or third floor?
So much goes into a decision to make a scanning hobby enjoyable.
If you want a starter scanner, I like the BC125AT. But you have to know that that one is limited to 512MHz at the top end so many public safety agencies operate above that frequency and most use digital trunking. If you want to get a digital trunking scanner, you will spend at least $250 to $300 for a used scanner. You might try looking in the classifieds here or on eBay. I'd look for something like a used BCD396XT, BCD996XT, BCD325P2, HomePatrol-1, Whistler WS1040, WS1065.