Logically Price Calculation

Hi,
I want to try different calculations based on width and height values.
For example;
width < x and height < y ; then $price*width*height
width < x and height > y ; then $price*width*height*1.2
width > x and height < y ; then $price*width*height*1.4
width > x and height > y ; then $price*width*height*1.6

Is it possible to do it at free version?
If possible, how can I write thses four formulas? I can not find it.

Secondly, is it possible to get X and Y values from custom fields?
Thanks at advance for your supoort.
Regards