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

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in fairly good shape, but not among the highest qualities.

2. Auction History:
- The average hammer price for similar coins in the past is 94.91 euros.
- The coin has been auctioned 96 times, of which it has sold 81 times, indicating good demand.
- Previous hammer prices for coins with similar conditions (around 70-80) have varied, but some examples are:
- 2022-03-10: 55 euros (condition 85)
- 2022-07-07: 60 euros (condition 80)
- 2023-05-23: 80 euros (condition 80)

3. Starting Price and Average Starting Price:
- The current starting price is 18 euros, and the average starting price is 77.73 euros.

4. Recent Trends:
- In the most recent auctions, hammer prices have shown a range that can reach up to 220 euros for higher conditions.

Based on this data, an estimated maximum purchase price for this coin, considering its condition and price history, could be between 80 and 120 euros. This is based on the fact that, although the condition is not the highest, there is good demand and a price history suggesting it could reach a higher price at auction.

Therefore, a reasonable estimated maximum purchase price could be 100 euros.