Bitrix24 is a free CRM with invoicing and quotes. Quote and invoice forms in Bitrix24 are fully customizable,
so you can add your logo, custom fields and rearrange information as you'd like. Quotes can be converted to invoices with just one click, and invoices can be either printed
out or emailed to clients. Most importantly, even a free plan in Bitrix24 comes with unlimited quotes and invoices.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.
Bitrix24 CRM manual is available here.
If you are interested in buying self-hosted editions of Bitrix24, which come with API, CMS and source code, can be easily customized and integrated with other tools, please download a trial version here.