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

1. Condition: The coin has a condition rating of 80 (MBC+), which indicates that it is in relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction history:
- The average hammer price for similar coins has been 166.69 euros.
- In previous auctions, coins with a similar condition (80) have had hammer prices that varied, but some examples are:
- 2020-11-10: 60 euros
- 2020-09-17: 75 euros
- 2018-10-16: 65 euros
- 2022-03-10: 65 euros
- 2022-10-19: 340 euros (a notably high price, but it may be an exceptional case).

3. Starting price and average starting price:
- The current starting price is 70 euros, and the average starting price in the past has been 105.95 euros.

4. Sales trends: The coin has been auctioned 60 times, of which 55 have been successful sales, indicating good demand.

Based on these factors, an estimated maximum purchase price could be in a range that considers the average hammer price and the price history of coins with similar conditions.

Given that the average hammer price is 166.69 euros and considering that the condition is 80, a reasonable maximum purchase price could be in the range of 150 to 200 euros. This allows for competition in the auction and the possibility that other bidders may also be interested in the coin.

Therefore, an estimated maximum purchase price could be 180 euros.