"The longer priced horses can be laid off [bet on with TAB] to offset their odds to whatever degree of risk you want. Just like the bookies do."

Hi crash you can lay or back for less than $6 on betfair. This is how.

If you want to lay a horse at $10 but you only wont to lay it for $2, you put in lower odds say $5 and your minimum $6 bet (nobody is going to take them odds) so your lay is on now you change your $6 to $8 submit the bet.
Now you have two lays on your sceen, one for $6 and one for $2 cancel the $6 lay and change the odds on the $2 lay to what you like.

cheers