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

1. Current Condition: The coin has a condition of 30 (BC+), which is significantly lower than previous conditions that ranged between 70 and 75. This suggests that the value of the coin will be lower compared to previous auctions.

2. Previous Auction Prices: Previous hammer prices for coins with conditions of 70 and 75 have been considerably higher, ranging from 95 to 190 euros. However, since the current condition is much lower, it is reasonable to expect that the hammer price will also be lower.

3. Starting Price and Average Hammer Price: The current starting price is 60 euros, and the average hammer price for similar coins in the past has been 130.63 euros. However, given that the condition is lower, the expected hammer price should be adjusted downward.

4. Sales Trends: The coin has been auctioned 9 times, of which it has sold 8 times, indicating a consistent interest in the coin, although the current starting price is lower than the historical average.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 70 to 90 euros. This is based on the need to adjust the price downward due to the current condition, while also recognizing the interest in the coin and previous hammer prices for higher conditions.

Therefore, a reasonable maximum purchase price could be 80 euros.