Given that the coin has a conservation rating of 100 (S/C), which indicates that it is in excellent condition, and considering that the starting price is 2300 euros, we can estimate a maximum purchase price.

Since there are no historical auction data for this coin, it is difficult to make a direct comparison. However, in the collector's market, coins in high conservation condition often reach prices that can be significantly higher than the starting price, especially if there is demand.

Taking these factors into account, an estimated maximum purchase price could be between 3000 and 3500 euros, depending on the demand at the auction and the interest from collectors.