So, Kevin, you correctly point out the difference between registering to vote and voting. It has been so many years since I registered to vote I have no idea what it costs. I could agree with you that no fee for registering, which is usually/often a one time action, is reasonable to consider. Still one should register, of course.
Registration determines the polling station for that person. In some elections, especially the general election, it would be untenable for folks to just go to any random polling site. They would not be able to keep 'books' of a whole county or state (or nation) at every polling place. Not to mention crowding. Everyone who works 'downtown' would want to leave their workplace and go to the closest polling station rather than the one associated with their home address.
Also, I'm always amazed (and thankful) that my registration seems to follow me with no effort on my part. I've had my polling station change several times, and I've moved a time or two which changed where I would vote, and I've always gotten a card in the mail telling where my 'new' voting place is without me even asking. How that happens I have no idea, but it is very convenient.
As for requiring an actual ID to register or to vote, be it the Driver's License or non-driving ID, of course we'd all like that to be no fee, along with yearly car registration etc. But many services are funded at least in part from those fees. It isn't all about wanting certain people to be able to vote or not, or drive, or whatever. Life costs money, and each jurisdiction has to determine how to provide it.
And not to forget about 'early voting'. There really is no excuse for someone not to be able to vote if they really want to. It allows for time and planning, arranging a ride, etc. Perhaps each area could do better with advertising it.
Candy