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.