Looks like a great deal. Total value = £139.96, so still in profit even if you happen to lose your entire £50 deposit.
I've checked the terms and can't see anything untoward? If you don't want to continue the ESPN subscription, you need to give 30-days cancellation notice otherwise you'll be charged for the fourth month onward.
I can't see anything in the terms about not being able to bet in-play, so if a team is winning by a fairly big margin with 15 or so minutes left then chuck the £50 on the win?
"We at 188BET have teamed up with ESPN and Top-Up Tv to offer you 3 months FREE ESPN plus a 250gb Freeview+ Digital TV recorder. All you have to do to receive all this is register a new account and place a bet or a combination of bets totalling £50 or more throughout November.
Click 'REGISTER AND BET NOW' and sign up for a new account. Then visit http://www.188promo.com/espn,
enter your details and place a bet or a combination of bets totalling £50 or more throughout November.
All existing 188BET customers need to do is simply click 'BET NOW', enter your details in the form that appears, then place a bet or a combination of bets totalling £50 or more throughout November.
There is no prize draw or complicated entry systems. As soon as you have followed the above steps you will receive 3 months ESPN and your Freeview+ box within one working week!"