it costs more to buy them together like that, because someone took the time and effort to put them together for you. If you aren't careful you could break the diode soldering wires to it, or pressing it into the module. Worth it I think
There you can find a sled with this same type of diode around $ 10 ..... but you have to harvest the diode yourself, take it from the heatsink and press-fit in the aixiz module (that you can find cheap on ebay, too) ..... and if you do some error, is easy to break a long open can diode, is for this reason that usually sellers ask for some more money, when they sell you diodes already pressed in modules, wired and checked.
Add your items on the cart ..... on the cart page, there's a button called "estimate shipping" ..... it open a popup asking you for the country and zip code, then give you the reply (shipping cost is based on destinations)