To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

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

2. Previous Auction Prices:
- In previous auctions, we have seen hammer prices that vary significantly. For example:
- In 2015, a coin with a condition of 75 sold for 151.65 euros.
- In 2021, a coin with a condition of 95 sold for 150 euros.
- In 2016, the hammer price was 282.93 euros, but the condition was not specified.

3. Average Hammer Price: The average hammer price for this coin is 104.14 euros, which gives us an idea of the general market value.

4. Price Trends: Observing the starting and hammer prices, it seems that prices have been increasing over time, especially for coins in good condition.

5. Current Starting Price: The starting price is 75 euros, suggesting that the seller expects a reasonable price, but it could be lower than the expected hammer price.

Based on this data, an estimated maximum purchase price for this coin, considering its condition and previous hammer prices, could be between 150 and 180 euros. This is based on the fact that coins in similar conditions have reached higher hammer prices in the past.

Therefore, a reasonable maximum purchase price could be approximately 160 euros.