Using Bet365 odds of 22/1 at the start of each game.
If you put £20 on the first goal method to be an own goal, then £20 on the next goal to be an own goal after every goal has been scored (excluding goals scored after 75th minute), you would be in profit of £1280.
I assume as the game gets later, the odds would increase, so possibly a bit more than that. Doesn't include the 2 8pm games last night, but even if it did, that's still over a grand profit.