There no calvins I know, but they do the job, and your getting 12 pairs for the price of 1 pair of calvins.
The boxers come in packs of 2 for £1.99, so a quid a pair. You can actually better this and buy the mens slips (if you prefer them) which come in packs of 3 for £1.99 so for £11.34 for 18 pairs of them woohoo!
There are different styles and colours, briefs, boxers, mens slips aswell as sizes.
Theres no need to buy 5 packs of kex, but its free postage on orders over £10 so thats why I said 12 pairs as I hate paying postage.
Use the code ff15 to get the extra 5% off (saves you 60p on the 12 pairs)
Go get em.