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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in an acceptable state, but not among the best qualities. This can influence the price, as coins in better condition tend to reach higher prices.

2. Historical Prices: By observing previous auction prices for coins with similar conditions, we can see that the hammer price has varied. For example:
- In recent auctions, coins with a condition of 75 have reached hammer prices of up to 470 euros (2022-04-27) and 420 euros (2022-10-19).
- The general trend shows that hammer prices for conditions between 75 and 85 have been in a range of 300 to 470 euros.

3. Starting Price and Average Price: The current starting price is 450 euros, which is higher than the average starting price of 268.45 euros. This suggests that the seller has high expectations for this auction.

4. Sales Trends: The coin has been sold in 93% of past auctions, indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 400 to 500 euros, considering that the starting price is 450 euros and that higher hammer prices have been reached in previous auctions for similar conditions.

Therefore, a reasonable maximum purchase price could be approximately 480 euros.