bourne for 15.. should i have waited?

[spy21der]

I just bought the bourne trilogy for 15 bucks from amazon. my question is. should i have waited? I bought my lil bro a braun razor for Christmas. Had no idea there was a promotion going on where if you spend over 130. you get a $50 promotion code. Well I got it today and couldnt believe my eyes. I had to see if it worked on absolutely anything.. so I apply to the bourne trilogy which is $75. The price then said $15.98. It applied some gift card too.. I have no idea why or how. So I bought it. Mainly because I feared if I did I would have lost the promotion and the gift card that it randomly applied. Does anyone know if I would have. anyway I have been waiting because I just know that the price is gonna drop. But I couldnt hold off on this. should I cancel and hope the promotion code works again? or just keep it?