To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the current condition of the coin (80 - MBC+) and the previous auction prices of coins with similar conditions.

1. Current Condition: The coin has a condition of 80 (MBC+), indicating that it is in fairly good shape, but not the best possible condition.

2. Previous Auction Prices: By observing the auction prices of coins with similar conditions (around 80), we can see that they have reached auction prices that vary, but generally, the auction prices for condition 80 have been in the range of 320 to 360 euros in previous auctions.

3. Average Auction Price: The average auction price for this coin is 353.38 euros, which is also a good indicator of the market value.

4. Auction Trends: The coin has been auctioned 52 times, with a high sales percentage (49 out of 52), indicating consistent demand.

5. Starting Price: The starting price is 200 euros, which is reasonable given the auction price history.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 350 to 400 euros, considering that the condition is good and that the auction price history supports this estimate.

Therefore, a reasonable maximum purchase price could be 400 euros.