Gift cards and the voucher machine
If you searched gift voucher, you may want a card you can sell, or the machine that pays out abilities. They are not the same object.
Gift cards you can haul
Fandom lists the sellable gift cards under Other in its item-request table. The separate Steam voucher discussion uses voucher cards for both random gift cards and special ability cards. Its account of selling cards before the machine existed concerns the demo era; it is not a general rule for current NG+ ability vouchers.
The machine and four abilities
Naguide counts four abilities and says you earn the vouchers by finishing quotas. The store description names two effects I am willing to repeat: call off the police once in a run, and repair every piece of loot and every tool at once. Cooldowns and the other two effects are not in that store paragraph, so they stay blank.
The store page also says you buy insider tips. Do not fold that shop menu into the voucher machine. Tips are scouting. Vouchers are run-changing abilities after you have already cleared.
Questions
What are the card values?
The Fandom item-request list includes gift cards at 50, 100, and 250 in the Other group. That is a request list, not a drop-rate table.
When does the machine show up?
Only Naguide describes the NG+1 requirement and buying the machine on the truck computer; it says completing quotas earns ability vouchers. A separate Steam discussion describes a missing demo machine and a slot machine after the first clear. Those are different version contexts, not a single unlock record.