Sky have effectively removed their free bet offers (other than the weekly fivers) in the past year, says something when they'd rather give you money back cash than a free bet.
I used to nick free bets wherever I saw them with Sky to build a decent Cheltenham portfolio, there were plenty of £50 free bet offers going back 12-18 months which became very useful.
My only other account is betway, they throw out 3/4 free bets a weeks each to a max £200, and the runner up on all TV races (plus selected weekday meetings) you can end up with a serious free bet balance...