There are two ways you can split the cost of a purchase using Pay By Group: Evenly and Custom. You’ll be prompted to choose your splitting method as the first step of creating your group, but you can also change this later.
Evenly divides the purchase into a number of equal shares. If you choose to split evenly you’ll select how many shares need to be claimed to complete the purchase (“Split evenly at least X ways”). When you invite others to join the group each invitee will choose the number of shares they’d like to pay for.
The Pay By Group system dynamically adjusts share prices as people join so that everyone pays the same amount for a share of the purchase. The members of a given group may pay different amounts from one another with the even split method, but only if they claim a different number of slots.
It’s best to choose “evenly” if the cost per person is the same for everyone in your group, even if one or more of the group members are paying for more than one person. Just set the minimum group size to the total number of persons participating, and have everyone choose the number of persons they’re paying for as their number of slots.
Custom allows each participant to enter their own individual contribution amount. If you would like, you can set a minimum contribution level (“Split custom where each pays at least $Y”) which requires your invitees to commit to paying at least that amount.
You can also recommend share amounts for each invitee, and those values will pre-populate their form when they join the group. However, they are not forced to use that amount, only to enter an amount equal to or larger than the minimum you set.