A lot of people who can't be bothered to even register to vote obviously wouldn't bid, many others would refuse to buy one or refuse to buy more than one on principle. Eventually if their were a set number of these, or a set number related to population, it would amount to stock and stabilize at a price you'd see on the ticker. Since someone might conceivably use a vote for decades and the government handles trillions every year, around $10,000 per capita per year they could go for very high values. 150,000,001 votes could be cast to give one self and allies every available penny.

If it were limit one per customer no one would bid more than one cent, no point, except maybe for Vote #1 or 'my lucky number' type stuff.

As to the merits of such a system, I don't think there are many pros compared to cons. There's always a temptation to find a way to remind everyone that freedom is bought with blood and gold but the problem with that is that most people know that and those who don't have failed to absorb that knowledge after 18+ years of living in a culture that devotes much of our holidays, entertainment/media, and schooling to reminding people of that. It mostly works, but a lot of people feel otherwise because they measure that commitment and devotion mostly in terms of how they'd expect them to manifest, either in type or degree, which is an understandable gauge but not a great one anyway.