Magento price calculations

[raj chahal]

Hi

Developing in Magento and selling rolls. The user can select from two width and can select from various lenths (1m, 1.25,1.5... 8m) from dropdown lists. Once selection is made the price is re-calculated, then the user can add to cart.

For instance if the price is £5 square metre, and the user chooses the 4m option and types in a length of 4.5m then the total cost should be 5 x 4 x 4.5

After reading numerous blogs I think I need to do 3 things:

1. create dropdowns (should this be coded or do i set up a configurable product - I need to give about 40 options for length for all similiar products! )

2. update the frontend price (jquery)

3. create observer to re-calculate price on server and add to cart.

Could someone help with this pls and let me know there to add the code for this to happen.

Thanks