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 fairly good shape, but not the best possible condition.

2. Current Starting Price and Previous Prices: The current starting price is 1800 euros. In previous auctions, hammer prices for coins with similar conditions (80) have varied, but there are examples where hammer prices have reached up to 3200 euros (as in the auction of October 2022).

3. Average Hammer Price: The average hammer price for this coin in the past has been 2387.53 euros, which can serve as a good indicator of what buyers are willing to pay.

4. Auction Trends: The coin has been auctioned 35 times, of which 32 have sold. This indicates good demand and consistent interest in the coin.

5. Comparison with Previous Prices: In previous auctions, the hammer price has fluctuated, but overall, prices have tended to be higher than the current starting price. For example, in the auction of March 2023, the hammer price was 4500 euros for a coin with a condition of 90.

Based on these factors, an estimated maximum purchase price could be in the range of 2500 to 3200 euros. This is based on the fact that, although the starting price is 1800 euros, the trend of hammer prices for coins in similar conditions suggests that buyers might be willing to pay more, especially if there is interest in the auction.

Therefore, a reasonable estimated maximum purchase price could be 3000 euros.