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

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

2. Auction History:
- The average hammer price in the past has been 91.97 euros.
- It has been auctioned 94 times, of which 54 have sold, indicating a consistent interest in the coin.
- The highest hammer prices in the past have reached significant figures, such as 840 euros in 2012, although this may be an exceptional case.

3. Starting Prices and Estimates:
- The current starting price is 25 euros, which is quite low compared to the average hammer price.
- The average starting price in the past has been 50.92 euros.

4. Recent Trends: In the most recent auctions, hammer prices have ranged from 50 to 130 euros, depending on the condition.

Based on this data, an estimated maximum purchase price for this coin, considering its condition and historical interest, could be in the range of 80 to 120 euros. This is based on the average hammer price and the price trend in recent auctions.

Therefore, a reasonable maximum purchase price could be 100 euros.