Voter ID: Is it a poll tax?

I've generally supported proposals for insisting on positive identification prior to casting a vote in a public election. After all, nearly every adult has either a driver's license or some other form of government-issued identification. If you have to produce it to buy alcohol or prescription drugs, what makes proving your identity at the ballot box any less important? However, during a debate with a friend over this issue, it was pointed out that the insistence that a prospective voter first obtain a government issued photo ID might be in violation of the 24th Amendment to the Constitution that prohibits the levying of a poll tax. Obtaining a government issued ID in this state (not a driver's license) costs $54, not an insignificant cost to a poor person or one on fixed income if all they ever needed the ID for is to cast their vote. It could very easily be a major impediment to a number of people, enough so to skew a close election.
So I've come to the conclusion that unless the federal government wants to provide free government issued photo ID's that the voter ID proposals are likely unconstitutional.
Which brings up another point: What about mail in voting (which I hate)? How do you insure that the person casting that vote is a legitimate voter? Could insisting on buying a $.50 postage stamp also be considered a poll tax (never mind the cost)?
Anyhow, I thought it an interesting topic.
So I've come to the conclusion that unless the federal government wants to provide free government issued photo ID's that the voter ID proposals are likely unconstitutional.
Which brings up another point: What about mail in voting (which I hate)? How do you insure that the person casting that vote is a legitimate voter? Could insisting on buying a $.50 postage stamp also be considered a poll tax (never mind the cost)?
Anyhow, I thought it an interesting topic.