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-), indicating that it is in an acceptable state, but not of the highest quality.

2. Current Starting Price and Previous Prices: The current starting price is 60 euros. In previous auctions, the average hammer price has been 130.73 euros, suggesting there is considerable selling potential.

3. Auction History: The coin has been auctioned 12 times, of which it has sold 11. This indicates good demand and consistent interest in the coin.

4. Previous Hammer Prices: Previous hammer prices for coins with a similar condition (70) have varied, but the highest recorded price was 90 euros in a recent auction.

5. Price Trends: The average starting price in previous auctions has been 98.92 euros, suggesting that the current starting price of 60 euros is relatively low compared to the average.

Taking all these factors into account, an estimated maximum purchase price could be around 90-100 euros, considering that the highest hammer price for a similar condition was 90 euros and the average hammer price is 130.73 euros. This suggests there is room for the hammer price to approach those values in the next auction.

Therefore, a reasonable maximum purchase price could be 100 euros.