I'm creating a jewelry store and the products' price will depend upon the price of gold. It would not be practical to update prices of all products everyday for the client so I was wondering if there was a way we could use a variable as the product price? I could update the price of gold from the backend and the price of all products will reflect the value.
For instance if the price of gold is $40/ounce and the product has 2 ounces, it's value shall be $80. If I update the price of gold to be $41, the price of product will become $82 and so on for all the products.
I know basic php but don't understand the phtml files of magento at all so a detailed explanation will be much appreciated.
what you need is price formula.
with a little programming you could set your product price to be function of weight.
here is a detailed explanation of how to implement price formula
either find an extension on magento connect that enables product prices to be function of product data or write this extension yourself, refer to the article above for basic explanation
One way to solve this is to use exchange rates. Either create a new custom currency or use some existing, but unused currency as a base and change exchange rate (basically coefficient) based on current gold price.