InvoWiz Pro 

InvoWiz is a modular invoicing system with an "Invoicing Wizard" that walks users step-by-step through the billing process.
invoice invoicing billing purchasing receipts purchase orders quotes

1PopCheck 

Retrieves emails from any standard POP3 server. Allows viewing, deleting and defining rules on emails along with many other administrative features. Emails from various accounts can be checked in a single window. Costs $9.99.
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