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

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The coin has been auctioned 11 times, of which it has sold 9 times. This suggests there is consistent interest in the coin.
- The average hammer price in previous auctions is 191.11 euros, which can serve as a good indicator of market value.

3. Previous Auction Prices:
- In past auctions, hammer prices have varied, but there are examples of hammer prices exceeding 190 euros, even reaching up to 460 euros in an auction in 2014.
- The trend of hammer prices appears to be increasing, especially in more recent auctions.

4. Current Starting Price: The starting price is 200 euros, indicating that the seller has reasonable expectations for a sale price.

5. Comparison with Similar Condition Prices: In previous auctions, coins with a similar condition (70) have reached hammer prices of up to 190 euros. Given that the coin in question has a better condition (75), it is reasonable to expect its hammer price to be higher than this.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 220 to 250 euros. This is based on the coin's condition, the demonstrated interest in previous auctions, and the current starting price.

Therefore, a reasonable maximum purchase price could be 250 euros.