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

1. Condition: The coin has a condition rating of 70 (VF-), indicating that it is in acceptable condition, but not among the best qualities. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Starting price and previous prices: The current starting price is 100 euros. In previous auctions, starting prices have varied, with an average of 86.88 euros. The average hammer price has been 60 euros, suggesting that coins do not always reach their starting price.

3. Auction history: The coin has been auctioned 8 times, of which it has sold 3 times. This indicates a moderate interest in the coin, but also that there is a significant number of auctions where it has not sold.

4. Previous hammer prices: In past auctions, hammer prices have varied. For example, in 2022 it sold for 70 euros, and in 2023 it was auctioned with a starting price of 150 euros, but the hammer price is not indicated.

5. Market trends: Given that the current starting price is 100 euros and considering the average hammer price of 60 euros, it is reasonable to assume that the hammer price could be in a similar range or slightly higher, given that the condition is acceptable.

Taking all these factors into account, an estimated maximum purchase price could be between 70 and 90 euros. This is based on the history of hammer prices and the condition of the coin. A price of 80 euros could be a reasonable starting point for an offer, considering it is slightly higher than the previous average hammer price.