To estimate a maximum purchase price for the coin in question, we can analyze the provided data:

1. Current condition: The coin has a condition of 75 (MBC), indicating that it is in quite good shape.

2. Auction history:
- The average starting price from previous auctions is 38.07 euros.
- The average hammer price is 45.18 euros.
- In previous auctions, the coin has had hammer prices that varied, but some examples are:
- 110 euros (condition 85)
- 50 euros (condition not specified)
- 38 euros (condition 75)
- 20 euros (condition 70)

3. Price trends:
- The coin has been auctioned 15 times, of which it has sold 11 times, indicating good demand.
- The last auction with a hammer price of 38 euros for a coin in condition 75 suggests that this is a relevant benchmark.

4. Estimation:
- Given that the coin's condition is 75 and considering the average hammer price of 45.18 euros, a reasonable maximum purchase price could be in the range of 45 to 55 euros, taking into account that the highest hammer price for a similar condition was 38 euros.

Therefore, an estimated maximum purchase price for this coin could be between 45 and 55 euros.