Should voter ID requirements (a la "SAVE America" act or similar) become law, constitutional prohibitions on poll taxes will lead towards every citizen getting an ID at no charge.
But there is no limit on what it might cost you to (1) obtain the required supporting documentation and (2) go to where you can submit your application at a time when they are accepting applications.
For older people and for poorer people these can be a significant problem. The fact is the for nearly all of its existence the US has not required much ID, meaning it is very hard to transition to such a requirement without disenfranchising many citizens. So far I don't think any proposal for stronger ID requirements has tried to address this.
That isn’t some accident of circumstance. The entirety of the purpose of voter id initiatives is to disenfranchise these very people.
There is a small group for whom it is literally impossible to obtain supporting documentation — this is the group that you're focusing on, but to my mind it's not that important.
There is a much larger group for whom the difficulty of obtain supporting documentation makes them statistically less likely to obtain it — and this larger group is the one targeted by voter ID laws to suppress their votes.
Because voter suppression strategies will absolutely not be abandoned, we're on an inevitable path towards national IDs.
The Supreme Court will do backflips to make the determination that they’re paid to make.