the eCommervce database works like this:
OptionsGroups - use this table to set the type of options you will offer. Color, Size etc.
Options - Use this table to define the options that belong to the different groups. Small, medium, large for the Size optiongroup and red, yellow green for the color options groups
productoptions - use this table to assign options to a product.
the price is set in the productoptions table so that different products can have different increments for the same option.
For product 1, it may only cost 1 dollar more for the large size, but product 2 may charge 3 dollars more for the large option.
by using the productoption table to define price increment amount, the price increment is dependant on the product and not the option itself, giving greater flexibility.