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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in fairly good shape, but not the best possible condition.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions (75 and 80), we can see that auction prices have varied. For example:
- In previous auctions with a condition of 75, the hammer prices have been around 90 to 140 euros.
- For condition 80, the hammer prices have been higher, reaching up to 295 euros in some cases.

3. Average Hammer Price: The average hammer price for this coin is 114.38 euros, which gives us a good reference.

4. Starting Price and Average Starting Price: The current starting price is 45 euros, and the average starting price in the past has been 71.82 euros.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of being higher, especially for condition 80.

Based on these factors, an estimated maximum purchase price for the coin in condition 75 could be in the range of 100 to 130 euros. This is based on the analysis of previous hammer prices and the current condition of the coin.

Therefore, a reasonable estimated maximum purchase price could be 130 euros.