Take a look over at Kids.Woot today—they’re selling 3-packs of Thames & Kosmos “Little Labs” sets for just $13 + $5 shipping. It looks to me like this deal came about because the packaging has changed (Woot is, obviously, selling the old labeling). For example, here’s the Physics Set on Amazon, where it (and the other kits) will run you between $13-$15 apiece.
So $18 for three is sounding like a pretty great deal to me, plus the shipping stays the same no matter how many you buy, so go ahead and get one of each bundle—six kits, total—for just under $31, or just about the cost of two kits from Amazon.
I’d say get these for the gift closet, but you know I’ll love you a little more if they’re for your own budding geeks.