STRING and right expression is of type BIGINT and the operator == is not valid

STRING and right expression is of type BIGINT and the operator == is not valid

Please Help. This should be so easy?

I have a lookup field to select an item by size from another form.
Now all I'm trying to do is automatically update the price of the item to a field called total.


if (count(iPrices[cabSize == input.cabSelect]) >0)
{
temp = iPrices [cabSize == input.cabSelect];
        input.total = temp.ssPrice;
}
else
{
input.total = 0.00;
}

...Error -> STRING and right expression is of type BIGINT

Thanks for your help.