DealCredits are used to send mail!
They're also used when you press Enhanced Search (to get phone numbers, emails, and additional addresses for the owner).
Set your reload amount in the Settings.
In Settings, Click Account.
In Account, Click "Set DealCredit Reload Amount"
Click the Reload Amount Page to Select it
Select Your Amount and Click the Check Mark or the Update Default Reload Credit Amount Button.
Note: The IOS version of the app does not have the Account option. Please go to DealMachine.com from your computer or your mobile web browser to access it.