To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the condition, previous starting and hammer prices, as well as behavior in past auctions.

1. Condition: The coin has a condition of 80 (MBC+), indicating that it is in quite good shape. This is relevant because coins in better condition tend to fetch higher prices.

2. Previous starting and hammer prices:
- The average hammer price for similar coins has been 371 euros.
- In previous auctions, the hammer prices for coins with a similar condition (80) have varied, but there are examples where they have sold for 320 euros and 490 euros.

3. Auction trends:
- The coin has been auctioned 12 times, of which it has sold 10 times, indicating good demand.
- The current starting price is 200 euros, which is slightly higher than the average starting price of 166.5 euros.

4. Estimation:
- Given that the average hammer price is 371 euros and considering that the condition is 80, a hammer price in the range of 300 to 400 euros seems reasonable.
- However, since the starting price is 200 euros, it is likely that bidders will be willing to pay a bit more, but they may not necessarily reach the average hammer price on this occasion.

Based on these factors, an estimated maximum purchase price could be around 350 euros. This reflects a balance between the condition, historical demand, and the current starting price.