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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins is 260.68 euros.
- The average starting price is 178.21 euros.
- In the past, coins with a similar condition (80) have had hammer prices that varied, but some examples are:
- 95 euros (2020-09-17)
- 75 euros (2018-09-19)
- 62 euros (2020-10-20)
- 120 euros (2022-04-26)

3. Sales Trends: The coin has been auctioned 91 times, of which 80 have been sold. This indicates good demand and sustained interest in the coin.

4. Current Starting Price: The starting price is 40 euros, which is relatively low compared to the average hammer price.

Based on these factors, an estimated maximum purchase price could be in the range of 200 to 300 euros, considering that the condition is good and that the hammer price history for similar coins supports this estimate.

Therefore, a reasonable maximum purchase price could be 250 euros.