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

1. Current Condition: The coin has a condition rating of 70 (VF-). This is an important factor, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The coin has been auctioned 15 times, of which it has sold 13 times. This indicates good demand.
- The average hammer price in previous auctions is 93.85 euros, suggesting that, in general, coins of this reference tend to sell for relatively high prices.

3. Previous Prices:
- In past auctions, hammer prices have varied, but there are examples of sales reaching up to 170 euros for coins with similar condition (80).
- The price trend for coins in the 75 to 80 condition range has been between 50 to 130 euros.

4. Starting Price and Estimates:
- The current starting price is 25 euros, which is quite low compared to the average hammer price.
- The average starting price in previous auctions is 60.36 euros, suggesting that the current starting price could be a good opportunity.

5. Proximity of Upcoming Auctions: There are 2 auctions scheduled in the coming days, which could increase competition and, therefore, the hammer price.

Considering all these factors, an estimated maximum purchase price for this coin could be in the range of 90 to 130 euros, taking into account that the condition is slightly lower than those that have reached higher prices, but there is still good demand and a price history that supports this estimate.

Therefore, a reasonable maximum purchase price could be 120 euros.