Need Database Software Suggestions

I am looking to establish a client / contact database for very small at home business to start but will be able to grow over time and not crash. I want the database to be able to build contact profile to include notes on correspondence received and sent, sales invoices and projects collaborated. Also data needs to be able to mail merge email and postal mail while extracting catergories of info.

The software needs to be both Mac and PC friendly.

My budget to spend on a database software is under $50.00 USA

My ability to program software is very limited unless a step by step instructions are available.

Does anyone have suggestions.