With Zoho Invoice for Google Apps, you can create, send, and track invoices and estimates. All you do is add customers, define your products or services, and then create an invoice.Also use attractive invoice templates for goods and services, or you can create templates on your own.
Add Users from your Google Apps account to your Zoho Invoice account and invoice them from within your Zoho invoice account
Get all your invoice related email notifications on Gmail and keep track of the invoices sent, payments received and lot more.
Import and get access to your Google contacts from within Zoho Invoice.
"With Zoho Invoice I've never had a question as to how anything works, it is extremely user friendly. "