Skybet used to have some really good sign-up offers. At the time of writing, they've scaled back a little bit. Their current offer is simply a no-deposit, £10 free bet. But a free tenner is a free tenner all the same....
However, a quick Google search brought up a "static" web page, with a "bet £10 get £20 free" offer; following the links on this took me to a sign-up page that honoured the promo I'd found (even if it wasn't their current promotion). A single £10 bet to unlock 2 x £10 free bets is not to be sniffed at. At the current rate I've been achieving (around 70%) that'd still be £14 risk-free.
As with previous free bets, this was all about getting some bets in quickly, taking whatever price was on offer, and getting out again - ideally "losing" all the bets at the bookies, pushing the value of the free bets through into the betting exchange(s). The qualifying bet was:
SkyBet: £10 on Rosario Central v Lanus draw result @ 2/1 (decimal odds 3.0)
Betfair: £9.52 against the draw at 3.2
The result went 2-1 to Lanus, so after commission, my Betfair balance increased by £9.04 which means it cost me 96p to access the 2 x £10 free bets.
Looking for a quick turnaround, I bet on the same game
Skybet: £10 on AC Milan (v Roma) @ 9/2 (decimal 5.5)
Betfair: £7.69 against AC Milan @ 5.80
twice. Roma went on to win 1-0 which meant after the game, my Betfair account was £15.38 better off. After commission, this equated to £14.61. Given that it cost 96p to place the qualifying bet, total profit for this promotion was £13.65
Not the best result and nowhere near the target 75% (13.65/20*100 = 68%)
But a result nonetheless. And, better still, every bet at SkyBet lost, meaning there was no messing about with withdrawing funds, and the betting exchange balance stayed nice and healthy!