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

1. Current Condition: The coin has a condition rating of 80 (MS+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Current Listing Price and Previous Prices: The current listing price is 475 euros. In the past, we have seen hammer prices that varied depending on the condition. For example, in previous auctions, coins with similar conditions have reached hammer prices ranging from 290 to 700 euros, depending on the condition and demand at that time.

3. Price Trends: The average hammer price for similar coins is 295.72 euros, which suggests that the current listing price is quite high compared to the historical average.

4. Demand and Supply: There are 3 auctions scheduled in the coming days, which could increase competition and potentially the hammer price.

5. Analysis of Previous Prices: By observing the hammer prices of coins with conditions ranging from 70 to 85, we can see that the price range is quite broad. However, since the condition of this coin is 80, we can expect the hammer price to be in the upper range of what has been seen previously.

Taking all these factors into account, an estimated maximum purchase price could be between 400 and 500 euros, considering that the listing price is 475 euros and that the condition is good. This also takes into account the possibility that demand in the auction may be high, which could push the price towards the upper end of this range.

To estimate a maximum purchase price for the coin with a grade of 80 (MBC+), we can analyze the historical data from previous auctions of coins with a similar grade.

1. Data from previous auctions:
- The grade of 80 (MBC+) has had hammer prices that vary, but generally, the hammer prices for coins with this grade have been in a range of approximately 300 to 400 euros in recent auctions.
- For example, in previous auctions, the hammer prices for coins with a grade of 80 have been:
- 340 euros
- 320 euros
- 360 euros
- 350 euros

2. Average hammer price:
- The average hammer price for similar coins has been approximately 323.88 euros.

3. Starting price:
- The current starting price is 400 euros, indicating that the seller expects a higher price than the average hammer price.

4. Recent trends:
- In the most recent auctions, hammer prices have shown a trend of increasing, especially for coins in good condition.

5. Estimation:
- Given that the coin's grade is 80 (MBC+) and considering the starting price of 400 euros, a reasonable maximum purchase price could be in the range of 350 to 400 euros, depending on the competition in the auction and the interest from other buyers.

Conclusion: An estimated maximum purchase price for this coin could be approximately 400 euros, as it is the starting price and aligns with previous hammer prices for coins of similar grade. However, if a more conservative approach is desired, a range of 350 to 375 euros might be more prudent.