Is my friend stuck with the one implant that he took from the begining or can he purcharse more implants from the armoury... if so for how much... or where in the core book can they be found (or any of the books ive got em all) thanks for any advice, help, or coments

One implant?

You start with all of the Mechanicus implants on that list.

You start off with all the implants, the only thing involving the implants. He doesn't know how to make use of every single one of 'em in every way. 'Least that's how I run them.

So he gets a number of implants to start out. See the tech priest character creation section. Most of these early ones don't do much or need training. Later implants can also be gain by taking various talents. These are generally "Mechadendrites". Also look at the end of the equipment section for additional implant, and limbs....

As pointed out in addition to all the implants on page 27 at the characters conception , the character has additional implant choices both in the core rulebook and the Inquisitors Handbook. For the more exotic items (Hermetic Infusion, Chem Gland) the GM might want to require the Peer Talent or RP adventuring.

And also as pointed out some require Talents to unlock or even Elite Advances. Hope he enjoys his newly discovered powers/ abilities!

Tons of help guys.. Thanks!