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 conditions.

2. Auction History:
- The average hammer price for this coin in the past is 75.42 euros.
- In previous auctions, hammer prices have varied, with some reaching up to 170 euros in superior conditions (such as in the December 2023 auction with a condition of 95).
- The most recent auction with a condition of 80 had a hammer price of 70 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 50 euros, which is slightly higher than the average starting price of 47 euros. This may indicate an expectation that the coin will sell for a higher price.

4. Price Trends:
- Observing the trends, it seems that coins in similar conditions have had hammer prices ranging between 70 and 80 euros in recent auctions.

Based on these factors, an estimated maximum purchase price for this coin could be between 80 and 100 euros. This is because, although the starting price is 50 euros, the condition and price history suggest that it could reach a higher price at auction.

Therefore, a reasonable maximum purchase price could be 90 euros.