would your dad be pissed about it? and how old are you? i say you talk to him before they show up, just say, i thought i needed new skis, and they were cheap (even if they weren't) my bro just did that when he got crowbars.
when you say you bought new skis, do you mean you ordered them with his credit card? if so, your an idiot for not asking, if not, fuck him, its your money do what you want with it