How can I make a dynamic matrix

Is there a way to store a calc in a dynamic matrix. For example I would like to store values for each price to the nearest .01 Something like item.price so for example say I have an item called item1 and I want to set that I sold 50 at 100.90 I could set the value item1.100.90 to 50. Sorry this is a crude example I am a new b

[KALYAN ACHARJYA]

It would be easy to undestand, if you can exaplain the question in maths language-

What you have (Input)?

What type of results you are expecting from that inputs?