Ordering Volks Head Purchase?

Volks only sells full dolls, they do not offer heads on their own. I believe Ruby is limited edition release, in the past she's been available on FCS for a limited time. (I might be wrong about this; there is more information about Ruby at Tenshi no Kichi).

If you want Ruby's head only, your only recourse is the secondhand market - Mandarake, Dollyteria, Yahoo!Japan auctions, here on DoA MP. Even then she is very likely to be sold with a body, so you'll either have to buy her as a full doll, or wait until you hit the jackpot with a head-only listing. You can make an account and buy directly from Mandarake and Dollyteria without a proxy. If you want to buy from Y!JA you will have to go through a shopping service proxy such as Buyee.

 

SD16 FCS is generally only offered at special events at Tenshi no Sato or through online FCS at VolksUSA. She was offered this month last year, but they seem to be off their old online FCS schedule. You would have to buy the full doll this way unless you find one secondhand. It is possible, but I really don't see the gems secondhand very often.