In a staking deal a backer will put up the stake (and mallet) with the aim of sharing the bounty with the slayer following a successful take-down of a vampire.
Most staking deals will involve make-up
Make up will be if a slayer is in the negative for you then he will be in a situation where he has to kill his way out of the hole (with the backers stake still)
For example -
night one you miss the heart and vampire gets away
night 2 you kill a vampire and get 1000 bounty
You will not just split the 1000 down the middle. the backer will take the 500 losses from the previous night. that will leave you with 500 to split down the middle.
That is the only legitimate way for a backer to make money. it is a fair way but the backer will always be the one to provide funds.
A backer can pull out anytime where a slayer can not. if you are - £4000 you will have to make attempts to get out of makeup or agree a specific time range with the backer.
being a backed slayer can be quite pressurising - as if facing vampires wasnt enough of a challenge.
Moral of the story always buy your own stake! You're the one taking the risk - have faith in your own ability.
If you cant raise enough to buy your own stake - get a proper/less risky job - like rat clearing all you need is a pipe for that.