NBA is a freaking goldmine for in-play trading. This Thunder/Suns game was a perfect example.
I backed the Under 216 pre-game at 2.06 (decimal odds on Betfair) and then put a Lay bet in at odds of 1.49 to go in-play. The Lay bet was matched after less than 10 minutes of play. 40% profit.
There's a problem with liquidity sometimes, but on days like today with just 2 games there was enough money in the Over/Under market to make it worthwhile.
If you're not too ambitious (greedy) you can pretty much guarantee a 15-20% profit if you pick the right spots. You want a game with an overly high or abnormally low Total (say >215, or <185). There will usually be a time during the game where it seems the Total line is getting out of reach (today's 1st quarter for instance), and the in-play traders always overreact.
Most of you guys are in North America and you don't have betting exchanges. You have to bet in-play with the books, which kill you with the vig. But if sports betting ever becomes legal in the States then hopefully betting exchanges will be allowed to operate. The NBA markets need more liquidity so I'm rooting for it.
Best sports for trading in-play:
#1. NBA
#2. 20/20 Cricket
#3. Tennis (distant 3rd).