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+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price and Average Hammer Price: The starting price is 60 euros, and the average hammer price in previous auctions is 136.65 euros. This suggests that, on average, similar coins have reached significantly higher prices than their starting price.

3. Sales History: The coin has been auctioned 242 times, of which 221 have been successful sales. This indicates good demand and consistent interest in this reference.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (80), we can see that they have reached hammer prices that vary, but some have gone for 150 euros or more in recent auctions.

5. Recent Trends: In the most recent auctions, hammer prices for coins of similar condition have shown an increase, which could indicate an upward trend in the value of these coins.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 150 to 180 euros. This range takes into account both the average hammer price and the condition of the coin, as well as recent market trends.