** Amazon.com AMZN.O rising 0.1% on Thurs after agreeing to pay $2.5 bln to settle FTC case over alleged unauthorized Prime sign-ups
** Settlement includes $1.5 bln fund to repay up to 35 mln Prime subscribers, with individual payments up to $51
** AMZN to add clearer opt-out and cancellation options, plus third-party compliance monitoring
** Stock flat YTD, lagging Nasdaq .IXIC which is up 16%
** AMZN recently at 30x expected earnings, well below 5-yr avg forward PE of 51