To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Coin Condition: The coin has a condition rating of 75 (MBC), which indicates that it is in fairly good shape, but not among the highest qualities (FDC).

2. Historical Auction Data:
- The average hammer price for similar coins has been 98.02 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices that varied, but some examples are:
- 25 euros (hammer price) in 2018.
- 40 euros (hammer price) in 2023.
- 35 euros (hammer price) in 2023.

3. Starting Price and Estimated Prices:
- The current starting price is 25 euros, and the average starting price for similar coins is 61.47 euros.

4. Sales Trends: The coin has been auctioned 147 times, of which it has sold 137 times, indicating good demand.

Based on this data, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering that the average hammer price is 98.02 euros, but adjusting for the condition and previous hammer prices.

Therefore, a reasonable maximum purchase price could be 85 euros.