This small tool lets you generate invoices for all items purchased by your clients or for services provided to them.
You can specify the currency you want to use for transactions, the thousands and decimal separators, and the type of taxes that apply.
The invoice can be customized, and you can include information about the client such as name, address, etc.
The most surprising thing about Express Invoice is that it lets you send the invoice by email or fax from the application itself (although you need to properly configure it for that first).
And there's more: Express Invoice incorporates a series of reports that let you check information like unpaid invoices, invoices issued during a certain time, for a specific client, etc. You can also check your invoices' history.
Supports Mac OS X 10.1 or higher.