Technomancer Spell cache

As the culmination of your early study of the fundamental forces of the galaxy, you have created a spell cache that allows you to store and access spells. Your spell cache could be a device like a handheld computer or technological implant: an item such as a ring or staff; or a symbol such as a brand, tattoo or other permanent modification to your body.

I'm having trouble understanding if the Spell cache is free or not. Since it seems to behave like the wizard's arcane bond I am under the impression that its also free. Lets say that I wanted to have a prosthetic arm as my cache (suboptimal, I know but it seems appropriate to my character idea.) do I have to subtract its value from my starting wealth?

I'd imagine that, if you want your spell cache to do things besides being a spell cache, you'd have to pay for the other item/functions.

Otherwise, some joker will say, "This battle cruiser is my spell cache".

Minor thread resuscitation (it seems recent enough to not be a thread necro :)

Any more thoughts on this now more people have seen the rules?

I think you have to pay for it, you just add the cache capacity to it for free. Arcane bonds weren't free in Pathfinder.

Yes they were.

Wizards who select a bonded object begin play with one at no cost. Objects that are the subject of an arcane bond must fall into one of the following categories: amulet, ring, staff, wand, or weapon. These objects are always masterwork quality.

Oh. Great, they aren't in Starfinder because they lack that language and giving away a free item without any limits would be horribly unbalanced. From an optimization standpoint I recommend a vostless tattoo rather than an item you might have to hold to use and that can be destroyed, at least until you can afford a Holographic Harrow Deck.