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 75 (MBC), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins has been approximately 34.94 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices that vary, but some examples are:
- 2021-03-18: 150 euros (condition 95)
- 2022-02-22: 35 euros (condition 75)
- 2022-04-27: 31 euros (condition 80)
- The trend shows that coins in MBC condition (75) can reach hammer prices in the range of 30 to 40 euros.

3. Starting Price and Average Starting Price:
- The starting price is 15 euros, and the average starting price is 30.24 euros. This suggests that there is considerable room for the hammer price to be higher.

4. Demand and Supply: The coin has been auctioned 45 times in the past, with a sell-through rate of 80%. This indicates that there is consistent interest in this coin, which may drive up its price at auction.

Based on these factors, an estimated maximum purchase price for the coin could be between 40 and 50 euros, considering that the condition is good and that interest in the coin is high. However, given the hammer price history, a more conservative price could be around 35-40 euros.

Therefore, a reasonable estimated maximum purchase price would be 45 euros.