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 (MBC), indicating that it is in fairly good shape, but not among the best qualities.

2. Auction History:
- The average hammer price for similar coins in the past has been 54.82 euros.
- In previous auctions, coins with similar conditions (around 75) have had hammer prices that varied, but some examples are:
- 40 euros (2024-09-19)
- 25 euros (2024-12-18)
- 45 euros (2022-10-18)
- 20 euros (2021-11-26)
- The trend shows that the hammer price can vary, but is generally found in a range of 20 to 60 euros for similar conditions.

3. Starting Price: The starting price is 15 euros, suggesting that the seller expects moderate interest in the coin.

4. Previous Hammer Prices: In past auctions, the hammer price has reached up to 220 euros for coins in better condition, but for conditions similar to the current one, prices have been lower.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 50 to 70 euros, considering that the condition is good and that the hammer price history suggests there is interest in this type of coin. However, since the starting price is 15 euros, it is likely that the final hammer price will not significantly exceed this range.

Therefore, a reasonable maximum purchase price could be 70 euros.