One thing people seem to forget when talking of the kit prices is the postage is included in the price hence "free" postage on checkout;
On a kit of this size the postage would be around $40-50 if not more, so taking that from the price makes it about $200 which isn't that bad.
The postage on the double Duelist would be even more, up around the $60-65 mark and again makes that base price quite reasonable for two big kits.