Re: 2 old saxophones
THe alto isnt worth too much - 1200 if it is REALLY REALLY, clean better than mint condition - almost new really, not worth a lot, but it is a excellent horn. Your son will have a VERY good horn to play at school if you give it to him. I am actually planning on getting a buescher as a backup to my III, mine is from around 1929 though and is goldplated.
The soprano however is a different story - it is worth more than the alto - its probably worth 1500 if it is next to new - I dont really see it going any lower than 800 bucks as long as it is playable and the tone holes havent been ground by some idiot technician. I would love ot have a gift like that - depending on condition and engraving and case and such, I might actually be a little overwhelmed (Though not likely ;)) if it were presented to me as a christmas gift - though I am a sax fanatic.