pengo go down to APrk race at 18:42 tonite.

look at Natty Nitro
someone is laying it @ $8.40 for $8
this means they are letting someone back it to lose $67.20. they are asking the punter for $8 to bet on it.
if the horse wins the layer here gets your $8
if it loses and you are the one backing it you will collect $67.20

dont forget the backing side (blue colour) contains the layers bets. this is where you as a punter or backer go to see what odds someone is giving you to back the horse they dont like.