To estimate a maximum purchase price for the coin that is going to be auctioned, we can consider several factors, including the coin's condition, previous auction prices, and the average auction price.

1. Coin Condition: The coin in question has a condition rating of 80 (VF+). This indicates that it is in relatively good shape, which can positively influence its price.

2. Previous Auction Prices: By looking at previous auction prices for coins with a similar condition (80), we can see that they have varied. For example, in past auctions, coins with a condition of 80 have reached hammer prices of up to 190 euros.

3. Average Hammer Price: The average hammer price for this coin is 98.9 euros, which is also a good indicator of the expected value.

4. Average Starting Price: The average starting price is 100.52 euros, suggesting that sellers are looking for a price in that range.

5. Market Trends: Given that the coin has been auctioned 1,295 times and has had a high sales percentage (971 out of 1,295), this indicates a consistent demand.

Based on these factors, an estimated maximum purchase price for the coin could be in the range of 150 to 200 euros, considering that the condition is good and there are precedents for higher hammer prices in the past.

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