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

1. Current condition: The coin has a condition of 80 (MBC+), which is lower than the condition of 90 from the previous auction. This suggests that the value could be less than the estimated price of 238.33 euros from the previous auction.

2. Starting price: The starting price is 40 euros, indicating that the seller has a low expectation compared to the previous estimated price.

3. Auction history: The coin has been auctioned once in the past but did not sell. This may indicate that interest in the coin is not high, which could affect its price.

4. Current demand: The coin will be auctioned again in the coming days, which could generate a bit more interest, but the fact that it did not sell previously may limit the price.

Given that the current condition is lower than that of the previous auction and considering the starting price, an estimated maximum purchase price could be between 60 and 80 euros. This reflects an increase over the starting price but also takes into account the lower condition and the auction history.

Therefore, a reasonable maximum purchase price could be 70 euros.