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

1. Coin Condition: The coin has a condition rating of 75 (MBC), indicating that it is in an acceptable state, but not of the highest quality.

2. Historical Data:
- The average hammer price for similar coins has been 116.27 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices that varied, with some examples being:
- 25 euros (2023-01-18)
- 54 euros (2020-10-20)
- 76 euros (2022-07-08)
- 110 euros (2023-03-22)

3. Starting Price and Estimates:
- The current starting price is 20 euros, and the average starting price for similar coins is 80.21 euros.
- The estimated price for this coin is 40 euros.

4. Auction Trends:
- The coin has been auctioned 81 times, of which 63 have resulted in sales. This indicates a consistent interest in the coin.

Based on this data, a reasonable maximum purchase price could be in the range of 80 to 120 euros, considering that the average hammer price is 116.27 euros and that the condition is 75. However, since the coin is not of the highest quality, a more conservative price might be around 80 euros.

Maximum Purchase Estimate: 80-100 euros.