We do not charge you to use BBC iPlayer. You do not require a television licence to watch programmes again, but do for live television. Further information on the licence and BBC iPlayer is here.
However, your ISP may have a download or upload limit, it's a good idea to contact your ISP and find out if there is a cap and what they'll do if you exceed it.
BBC iPlayer on mobiles
Although we don't charge you for access, 3G users should check with their operator to confirm costs.
For further help you can Contact Us, or you can discuss this issue at the BBC iPlayer messageboard.