STUFF can happen SO FAST on the water that you'd be stupid NOT to wear one G2.....I buy the BEST type 1 offshore for my son I can, and I wear the std pfd, this year I bought him a new one without the bobbin in it......we had too many problems with the damn thing going off inside the console while washing the boat

$14 a shot to rearm it gets expensive real quick! I figure he's old enough now to remember the first rule if he goes over....pull the cord.
Where to buy...any West Marine store or Boat US, Cabelas has them too. Make sure you get one with the highest bouyancy you can, there are some cheapies out there you want to stay away from! SOSpenders is a good line, under $200 at West etc. Get the one with the mirror and whistle built in too....that way if something does happen you can get someone's attention!