When pulling the alert I plan on adding a one-time addon cost to the plan for each alert. Now first question is can we add the addon with a custom price because in our scenario the same type of alerts can come in with different prices. 

Another Question since we require daily batch processing of all the alerts for that day it would be perfect if the plan can renew / process daily. I only see the option for weekly monthly and yearly. So does Zoho subscription support daily cycle units? 

My only other option would be one-time transactions but I really like to use addons so we can perform reports on them.