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), indicating that it is in fairly good shape, but not among the best qualities.

2. Previous Auction Prices:
- In 2020, a coin with a condition of 85 had a starting price of 6500 and an estimated price of 7500, although it did not sell.
- In 2021, coins with a condition of 85 were auctioned and sold for 5000 and 5200.
- In 2019, a coin with a condition of 30 sold for 1900, indicating that the price can vary significantly with the condition.

3. Average Starting and Final Prices: The average starting price is 2900 and the average final price is 3080. This suggests that, in general, coins of this reference tend to sell above the starting price.

4. Sales Trends: The coin has been auctioned 6 times, of which 5 have sold, indicating a consistent interest in this reference.

Given that the condition of the coin is 75, which is lower than the conditions of 85 that have sold for higher prices, and considering the average final price of 3080, an estimated maximum purchase price could be set at a lower range.

Estimated Maximum Purchase Price: Based on the previous information, a reasonable maximum purchase price could be around 2500 to 2800 euros. This takes into account the current condition and previous final prices, as well as the interest in the coin.