I,bought,online,a,gift,card,but,could,not,redeem,to,my,account.,Pl's,Help

Apple Store cards can't be redeemed onto an iTunes account, they are for use in Apple shops and their online store. Try contacting the site that you bought it from and see if they will exchange it, or try contacting iTunes Support (for the country that the card is for, and which is therefore the country on your iTunes account) and see if they can/will add its value to your iTunes account : http://www.apple.com/support/itunes/ww

If you want help you have to provide details. Why can't you redeem it onto your account, what happens ? If you are getting an error message what does it say ?