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 75 (VF), indicating that it is in acceptable shape, but not among the best qualities. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- In the past, this coin has been auctioned 3 times, of which it has sold 2 times and not sold 1 time. This suggests that there is interest in the coin, but also that there may be a limit to what buyers are willing to pay.
- Previous starting and final prices are relevant. In 2015, the starting price was 55.15 and 55.87, with a final price of 55.15 in the first auction. This indicates that the market has valued this coin in a similar range in the past.

3. Average Starting and Final Price: The average starting price is 57.01 and the average final price is 55.15. This suggests that the market has been willing to pay around this range in the past.

4. Estimated Price: The estimated prices of 68.93 and 69.84 in previous auctions indicate that, although the final price was lower, buyers were willing to consider higher prices.

Given all this, a reasonable estimated maximum purchase price could be set in a range between the average final price and the previous estimated price, adjusted for the current condition.

Considering that the condition is 75 (VF) and that interest in the coin seems to be moderate, a reasonable maximum purchase price could be around 65 euros. This reflects interest in the coin, but also takes into account its condition and price history.