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

1. Current Condition: The coin has a condition rating of 80 (MS+). This is an important factor, as coins in better condition tend to fetch higher prices.

2. Starting Price and Average Hammer Price: The starting price is 100 euros, and the average hammer price in previous auctions is 141.7 euros. This suggests that, in general, coins of this reference tend to sell for above their starting price.

3. Sales History: The coin has been auctioned 83 times, of which 80 have been successful sales. This indicates good demand and sustained interest in this coin.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (80-85), we can see that they have reached hammer prices that vary, but some have exceeded 200 euros in similar conditions.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of being higher, especially for coins in similar condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 160 to 200 euros. This is based on the hammer price history and the current condition of the coin. However, it is important to note that the final price may vary depending on the competition in the auction and the interest of other buyers.