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

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in relatively good shape. This suggests that its value should be above that of coins in worse conditions.

2. Auction History:
- The average hammer price for this coin in the past has been 163.52 euros.
- The highest hammer prices have reached up to 953.96 euros in condition ratings of 90.
- In recent auctions, the hammer price has varied, but it has remained in a range that suggests consistent demand for this coin.

3. Starting Price and Average Starting Price:
- The current starting price is 75 euros, which is below the average starting price of 101.06 euros. This may indicate a buying opportunity, as the starting price is lower than the historical average.

4. Recent Trends: In the last auction, the coin sold for 100 euros with an estimated price of 160 euros, suggesting that there is interest in the coin at higher prices.

Based on these factors, an estimated maximum purchase price could be in the range of 150 to 200 euros, considering that the condition is good and that the price history shows that coins in similar conditions have reached higher prices.

Therefore, a reasonable maximum purchase price could be 200 euros.