Below is a list of the functionality and limits that differ between billing plans. It does not include Wild Apricot functionality and limits that are shared by all plans.

PlanMax.
contacts
Max.
admins
Storage
limit
Excluded
features
Trial5005100 MBCustom domain
Free501100 MBOnline payments 
Custom domain 
Theme overrides
Site search gadget
Scheduled emails
Online store
Mobile apps
Personal100unlimited2 GBnone
Group250unlimited2 GBnone
Community500unlimited2 GBnone
Professional2,000unlimited2 GBnone
Network5,000unlimited2 GBnone
Enterprise15,000unlimited2 GBnone
Global50,000unlimited2 GBnone