Pricing structure update! Please read new Tier pricing documentation. Choose either single site price at $5 or a lifetime license for $45 – Neither pricing option includes support.

Update March 2017: There is only one price point but your license is a lifetime license, no support will be offered for this product. Feel free to download/contribute/fork this plugin for free on GitHub.

WordPress Invoice Pro is a quoting & invoicing plugin for keeping track of client. Create unlimited invoices and send each invoice via email to a client and view the invoices on your website domain, just like a regular post or page.

With encoded permalinks, the invoice with be super secure and harder to find publicly (this option can be turned on or off via the settings).
Example: youdomain.com/invoice/9id9i2jf9i23k0fgj107kf

I would also suggest setting the quote/invoice as “password protected” to enhance the security in case the quote or invoice has sensitive material. Note: The password is emailed to the client when you click “email client” (if a password has been set) so they can access it.

Feel free to download/contribute/fork this plugin for free on GitHub

Screenshots