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 75 (MBC), indicating that it is in an acceptable state, but not among the best qualities (FDC).

2. Previous Auction Prices: By observing the hammer prices of coins with similar conditions, we can see that the hammer prices for coins with conditions ranging from 70 to 80 have varied, but they have generally sold between 270 and 400 euros.

3. Starting Price and Average Hammer Price: The current starting price is 350 euros, and the average hammer price in previous auctions is 313.25 euros. This suggests that the starting price is reasonable, but it could be a bit high compared to the average hammer price.

4. Auction Trends: The coin has been auctioned 160 times, with a sell-through rate of 96.25% (154 out of 160). This indicates high demand and consistent interest in this coin.

5. Recent Hammer Prices: In the most recent auctions, hammer prices have been in the range of 300 to 400 euros for similar conditions.

Based on these factors, an estimated maximum purchase price for this coin could be around 400 euros. This is because, although the starting price is 350 euros, the interest in the coin and its condition suggest that it could reach a higher price at auction. However, it is important to keep in mind that the final price will depend on the competition in the auction and the willingness of other bidders to pay.