call float variable from 2 strings?

Hi,
I need to figure out how to call a float variable from 2 strings.
Here is my code to help your understand.

var money : float;
var Testprice : float = 1000;

function OnMouseDown () {
var purchase = gameObject.tag; //tag is "Test"
var purchasePrice = purchase + "price";
money = 3000;
if (money => purchasePrice) // i cant get this to work?
{
	Invoke( purchase, 0f );
}
}

You could use reflection (google it)

Or you could create a helper method

private float GetPrice (string itemName){
    switch (itemName){
        case "TestPrice" :
            return testPrice;
        case "OtherPrice" :
            return 572;
    }
    return 0;
}