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

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins in lower condition.

2. Auction History:
- The average hammer price in previous auctions is 35.15 euros.
- The last auction where this coin was sold (2022-09-14) had a hammer price of 95 euros with a condition of 85, suggesting that coins in better condition can reach significantly higher prices.
- In other auctions, hammer prices have varied, but the range seems to be between 15 and 95 euros, depending on the condition.

3. Starting Price and Average Starting Price:
- The current starting price is 25 euros, and the average starting price in previous auctions is 23.27 euros. This suggests that the starting price is reasonable and aligns with the history.

4. Sales Trends: The coin has been sold in 13 out of 15 auctions, indicating good demand.

Based on these factors, an estimated maximum purchase price could be set at a range above the average hammer price, given that the condition is good and there is a history of high prices in previous auctions.

Estimated Maximum Purchase Price:

We could consider a maximum purchase price of around 70-80 euros. This is based on the fact that the condition is good and there are precedents for higher hammer prices in the past. However, it is important to note that the final price will depend on the competition in the auction and the demand at that time.