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

1. Coin Condition: The coin has a condition of 25 (BC), which is quite low. This generally implies that the final price will be significantly lower than that of coins in better condition.

2. Historical Data: By observing the final prices of coins with similar conditions, we can see that the final prices for coins in BC (Below Circulation) condition tend to be low. For example, in previous auctions, the final prices for coins with conditions of 30 or 25 have ranged from 15 to 36 euros.

3. Average Final Price: The average final price for this coin in the past has been 128.83 euros, but this includes coins in better conditions. For a coin with a condition of 25, it is reasonable to expect a much lower final price.

4. Starting Price: The starting price is 10 euros, which indicates that the seller is willing to accept a low offer, which may influence the final price.

5. Market Trends: Since the coin has been auctioned 266 times and has had a considerable number of sales (230), this suggests that there is consistent interest in this coin, but the low condition may limit that interest.

Based on these factors, an estimated maximum purchase price for this coin, considering its low condition and historical prices, could be between 15 and 30 euros. This reflects a range that is reasonable for a coin in BC condition, taking into account past auctions and market interest.

To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially considering the current grade of the coin (30 BC+) and the auction prices of coins with similar grades in the past.

1. Current Grade: The coin has a grade of 30 (BC+), indicating that it is not in the best condition. This generally translates to a lower auction price compared to coins in better condition.

2. Historical Auction Prices: By observing the auction prices of coins with similar grades (around 30), we find that:
- In previous auctions, coins with a grade of 30 have reached auction prices between 15 and 30 euros.
- For example, in the auction on 2018-12-11, a coin with a grade of 30 was sold for 15 euros.

3. Price Trends: The average auction price for this particular coin is 107.29 euros, but this includes coins in better condition. Given that the current grade is quite low, it is unlikely that this price will be reached.

4. Starting Price and Estimates: The starting price is 12 euros, and the average starting price in the past has been 54.55 euros. However, since the grade is low, it is reasonable to adjust expectations towards a lower auction price.

5. Final Estimate: Taking all these factors into account, a maximum estimated purchase price for this coin, considering its grade and historical auction prices, could be between 20 and 30 euros. This reflects a balance between the current grade and the auction prices of similar coins in the past.

Therefore, a maximum estimated purchase price for this coin could be 30 euros.

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

1. Coin Condition: The coin has a condition of 95 (S/C-), which indicates that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Price History: By looking at previous auction prices for coins with similar conditions (around 95), we can see that auction prices have varied. For example:
- In 2019, a coin with a condition of 95 was auctioned for 30 euros.
- In 2020, another coin with a condition of 100 was auctioned for 65 euros.
- In 2022, a coin with a condition of 95 was auctioned for 25 euros.

3. Average Auction Price: The average auction price for this coin is 20.06 euros, which is also an important indicator.

4. Recent Trends: In the most recent auctions, the auction prices have shown a range that can go from 12 euros to 55 euros, depending on the condition and demand.

Based on these factors, an estimated maximum purchase price for the coin in question could be in the range of 30 to 40 euros. This range takes into account the good condition of the coin and previous auction prices for similar coins.