I need software for my new business, and I don't know how it's called! Help!

Hello.

Recently I decided to quit working for a boss, and start my own Translation Service. No bosses and no people working for me. Just me.

I need some kind of software that will keep track of every client that will come to me and bring papers/books/data/websites for me to translate. I want it to keep all the details of the client (name, ID number, Social Security number, adress etc). Something like a database.

Then, I want a second, separate feature: I want it to be able to 'call' a name from the database, and create a specific receipt of my services for that client. I want it to ask the price of the specific service I provided, make me input the money they gave me, and print out the change also!!

Lastly, and this is the hard part:

I have a personal formula that creates the final price: It is the number of the translated pages MULTIPLIED by a factor which depends on the document kind (eg legal documents = 6, medical = 9) due to various difficulties, and the result divided by the days asked to deliver. In that way, my clients can ask their translations to be delivered in a later date, so that the price will be cheaper.

               difficulty factor X pages

Final Price = ------------------------------ days

So, I want that software to be so customizable, so that it will allow me to enter all this data.

I am so desperate after numerous google searches, that I am willing to get back to my QuickBasic years and create a custom software, but its been a hefty 10 years since I was programming. Back then, I could have done this piece in 2 days max. But I haven't used qb for all these years...

Any software that comes close?

EDIT: Of course, I want it to be open source and free.