Those are very good starters; I used those right after cigalikes, and found them very satisfying, compared to the cigalikes -- however that's not a very good price for such outdated hardware -- try this instead:
http://www.vaporbeast.com/kanger-t3s-clearomizer-tank.html -- only $3.95 instead of $5.99, and VaporBeast also processes orders a bit more quickly than MyVaporStore. And if you buy from VaporBeast, use this coupon code: FIVEOFF -- for a slightly even better price.
Andria
ETA: For an answer to the other part of your question: I don't think there would need to be a signature just for hardware. However if you ever do buy something online that does require a signature, I'm pretty sure that whoever signs for it must be at least 21. Maybe 18. And that might actually come to pass, with ejuice and/or nicotine, if all the vape-haters get their way, but I don't think it's the case right now, in the US.