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+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Prices: By looking at previous auction prices for coins with similar conditions (around 80), we can see that the hammer prices have varied. For example:
- In previous auctions with a condition of 80, the hammer prices have ranged from 110 to 190 euros.
- A specific case is the auction on 2021-06-22, where the hammer price was 190 euros.

3. Average Hammer Price: The average hammer price for this coin is 175.56 euros, which can also serve as a reference.

4. Starting Price: The current starting price is 100 euros, indicating that the seller expects a minimum price of 100 euros.

5. Auction Trends: The coin has been auctioned 62 times, of which it has sold 56 times. This indicates good demand and consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 180 to 220 euros, considering that the condition is good and there are precedents for hammer prices in that range.

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