When looking for a tool to manage invoices and billing here's some simple guidance.
Think process first and then technology. Consider the projected future needs of your projects, what the customer demands in the way of invoice backup for services, rates and the like if you work on time and material jobs.
Write a specification that details these needs and send it to tool vendors. Ask for competitive quotes and on-line demonstrations or trials if they are available. Select your tool carefully and let your specification drive the tool, not the other way around.
Remember:
1. An electronic computer software package is not a system. One cannot acquire a system by acquiring computer capability.
2. One acquires a system by conducting systems analysis, achieving a design and processes by working with the people who will run the system. This is hard work and time consuming. Processes are improved and made more efficient by modifying user behavior not by automating it.
3. Once system and analysis and system design are complete one chooses tools to assist in running the system. The adequacy of a computer tool is driven by the requirements of the most efficient system design.
4. The biggest mistake implementation teams make is to believe they are buying a system when they buy a software tool or let the software drive the systems analysis process. That is like asking a mechanic to drive a wrench from New York to St. Louis. It has resulted in millions of dollars wasted and plummeting efficiency in many organizations, large and small.
5. It is necessary to design a system and processes unique to the company to meet user requirements before going shopping for computer tools. If you do not you will be pigeon-holing your company into a COTS mentality and become a slave to the company that owns the source code. If you want anything changed it costs a big buck.
Depending on the size of your business, you could use either QuickBooks (Pro, Premier, Enterprise) or Sage 50 (formerly Peachtree, Complete, Premium, Quantum). Both have most of the small business market for accounting and they offer industry specific applications (Manufacturer, Contractor, profesional services firms, etc). They both allow for invoicing clients by email straight from the accounting software.