Say you anchor an armor spell on yourself that goes off when a "Detect Bullet" spell does. Once it goes off, can you turn off the spell, or does it keep on going like a quickened spell? I hope to God there's an "off" switch.

I can't say it sounds very useful. It would turn on just because you grabbed your gun. Or stood next to your street samurai. Or most anyone else.

If you cast the spell, I'd say yes. Otherwise, no.

So you can cast the spell again to reset the anchor without spending karma? Can you do this from the astral plane?

Anchored spells, once activated, are permanent, quickened ones. If you want an on/off effect, you need an anchoring focus, which is a triggerable preset sustaining focus that costs triple karma to bond and is usable only if you know anchoring metamagic.

Horrible karma/metamagic sink, few benefits.

In any case, a permanent Deflection spell (new in SM) can be permanently sustained without drawing the "glowing shield" attention of Armor, and against ranged fire it's better than Armor, as successes combine with your Reaction test to make the attack potentially miss entirely, rather than just soak damage. Yes, it doesn't work against melee, but that's a pretty good tradeoff, IMO.

I think I'll make it so you can turn it off from any distance.

How much would an anchored deathtouch on a bullet cost?

How much would it cost you to buy the book?

Force karma. Unresuable. Knock yourself out.

No, I mean in nuyen for a contact to anchor the spell.

I don't know. How much for a contact to blow karma to bind a patrolling spirit for a year? How much to make a ward permanent for Force karma? Take those numbers and triple them, I would guess, because any mage can do those tricks; damn few can anchor.

Or: more than it's worth. You could probably just hire a competent assassin to do it with his own methods for considerably less.

Upon further thought, I doubt such a contact could realistically be found. Anchoring is not likely to be a second metamagical technique, and is likely to be rare because it's so expensive in karma terms. Does your character know a Grade 4-6 initiate who knows the technique? Why? Does his backstory explain both why he has the technique and why he'd rather take your money than keep his karma and learn a new spell (and a half)? Does his backstory explain why he'd know this technique as well as the forbidden (or highly restricted) Death Touch spell? Why he learned Death Touch instead of the more utilitarian Manbolt for self defense? Biggest of all, why he'd be willing to put his signature on a deadly spell that you're going to leave in someone's body?

If something seems impossible or like a bad idea to a character, it's probably not going to be easy to get a NPC to do it for you.

You shouldn't need a contact. The same wagemages that provide foci to the big chain talismongers should also provide anchors to them. They are karma intensive, yes, but they're also easily transferable comodities, unlike partoling spirits and wards. Previously, professional enchanters who do nothing but make healing potions and similar disposable anchors were cannon (although this didn't mesh with the game rules; people who sold anchors for a living risked dying to drain). With the new anchoring rules, professional anchormaking is actually a viable business and the same rules can cover aspected witches' charms, which were introduced in SOTA '64.

I think you haven't looked carefully at the anchoring trigger rules. Contact trigger of "not the creator" is the only practical noncustomized general use possible for other users, and the difficulties of transporting/handling such an item without accidentally triggering it prematurely are close to insurmountable, especially if you keep the old SR3 rules that the reason you can manabolt a person in full armor is because his aura sticks out of his body a few inches. So they're not really easily transferable at all. I suppose custom detection spell triggers are a way to by pass this limitation, but that's going to make your base effect even more expensive and limit the utility of commercial anchors to the limits of whatever custom spell the creator knows.

In any case, buying a horribly expensive one shot heal spell just so you don't have to carry around a medkit and spend time/karma on First Aid skill is one thing, going to a chain store and saying "I'd like a Death Touch bullet, please" is entirely another.