Tracking Expenses and Re-Invoicing
You’ll now find that all Ronin accounts come with a simple expense tracking feature. It’s straightforward and the goal is simple: To allow you to track expenses incurred on behalf of clients and re-bill them during invoicing.
The interface is self explanatory:

You can easily add new expenses and view them under the “Expenses” tab.
Where it gets interesting is when it comes time to invoice your client, you’ll find that Ronin automatically detects any outstanding expenses that have not been invoiced:

Along with time tracking, we hope this provides a comprehensive tool for tracking what you’re owed so you never have to go through the trouble of under-invoicing.

[...] your data in Ronin, and one of the most common requests is for a better way to organize and manage expenses as they’re tracked in Ronin. There were a few implementation options that we considered, but [...]
Announcing Expense and Product Tags | Ronin Blog
29 Feb 12 at 9:40 pm