To estimate a maximum purchase price for the coin in question, let's consider several factors:

1. Current starting price: 200 euros.
2. Condition: The coin has a condition rating of 75 (VF), indicating that it is in fairly good shape, but not the best possible condition.
3. Auction history:
- In 2015, the coin was auctioned with a starting price of 90 euros and sold for 170 euros.
- In 2019, the starting price was 210 euros and it sold for 240 euros.

4. Average hammer price: 205 euros, which is a good indicator of the current market value.

5. Trends: The coin has seen an increase in the hammer price in the 2019 auction compared to 2015, suggesting that its value is rising.

Given that the current starting price is 200 euros and considering the auction history, with a hammer price of around 240 euros in the previous auction and an average hammer price of 205 euros, it can be estimated that the maximum purchase price could be in the range of 240 to 260 euros, taking into account the upward trend and the condition of the coin.

Therefore, an estimated maximum purchase price could be approximately 250 euros.