Net stake
The net stake is the imbalance between your total matched BACK stakes versus your total matched LAY stakes on a selection. In the example shown below, the total matched BACK stakes are £100, but the total matched LAY stakes are £0.00. Therefore the net stake is £100 (£100 - £0.00). You would need a £100 LAY bet to close the net position (to make the matched stakes equal), so the Net stake is shown in pink.
Trading involves trying to get bets matched on both sides of a selection. You are aiming to BACK at a high price and LAY at a lower price to make a profit once the net position is closed, i.e. with equal stakes matched on both sides of the selection (not including stakes used for greening up).
On the ladder
A - Click on the net stake to copy it to the stake box. Then you can manually place the net bet (in this case by clicking in the lay column).
or
B - Click here to send a bet for the net stake at the best available price (1.78 in this example). If matched, this will clear the net position on this runner.
or
C - Click in this column ('Net To') to choose the profit that you want to achieve if the net bet is matched at your chosen price. The bet will be sent at the price corresponding to where you clicked.
Sending a bet for the net stake on the ladder does not cancel unmatched bets. You can cancel them by clicking the red cancel button.
'Free bets'
In the picture above, the net position has now been closed and so the potential profit or loss has now been locked in on this selection. However, for the profit or loss to actually be realised, this selection still has to win. If this selection doesn't win, then your bets on this selection won't make any profit or loss. So in the example above, if the selection wins then a profit of £1.00 would be received, but if the selection loses then no money is lost, so this is what some people call a 'free bet'.
If you want to guarantee to receive some profit (or loss) on your bets, regardless of which selection wins, then you should Green Up instead of just closing the net position. The picture above shows that the position has not yet been greened up, but it could be greened up for a guaranteed profit of £0.54 regardless of which selection wins.