I am torn between my husband and child!! Help!!?

First, I'd like to start off by saying.. I have a problem with money.. I am frivolous with it. I like shopping and having nice things, not only for myself but, my child and my household. My husband is more conservative with his. His likes to save and never buys himself anything. My son's birthday is coming up and he wants a playstation 3. He's wanted it since this past Christmas but, we decided to get him a motorcycle instead (battery powered). He really loves the motorcycle and rides it everyday but, he still wants a playstation 3. I have a friend that is selling one for $350 with games and an extra controller. To me this is a great deal but my husband says it's too much money to spend on 1 gift for a birthday. He says we should get it for him for Christmas. I really think my son deserves this and I know how badly he wants it. (He got straight A's on his report card) I could buy this with my money but, my husband doesn't see it as a deal he just sees this as a way for me to spend more "unnecessary" money. I feel that since he has already said he doesn't think that we should make this kind of purchase right now if I do it anyway, is this disrespectful? Only serious answers please. Thanks