I've no idea as to the actual margins on each of the shop products. However I went in not long after the new home strips were released looking for one for my daughter (around 18 month size). The nice young chap told me they had sets - shirt and shorts but not socks like they used to for £40. I decided against it as I thought the cost was far to high for a tiny set that'll only fit for a few months. To be fair the lad did say that they would like to sell them cheaper but they don't make much on them as it was. Take from that what you will.
Even though I said I wouldn't, I bought an adult one for myself instead, it'll get more use, so economically it was better you see . I've now got 2 as I got one as part of the FFIT programme last night!