One person heads the pool and collects the money via PayPal while keeping track of everyone in the pool. You are allowed to buy as many shares in the pool as you want. And if we hit the jackpot the money is divided amongst the participants based on how many shares each person bought.
For example.
If each share costs $1
And the jackpot is $100
Person "a" bought 1 share
Person "b" bought 2 shares
Person "c" bought 3 shares
Person "d" bought 4 shares
If we win you take the jackpot divided by the number of shares sold to figure out the value of each share.
In this example each share is worth $10. So if we hit the jackpot
Person "a" wins $10
"b" wins $20
"c" wins $30
"d" wins $40