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 80 (MBC+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for this coin in the past is 187.67 euros.
- In previous auctions, we have seen hammer prices that varied significantly, ranging from 90 euros to 650 euros, depending on the condition and demand at that time.
- The most recent auction (2023-12-13) had a hammer price of 245 euros with a condition of 80.

3. Starting Price and Estimates:
- The current starting price is 175 euros, which is slightly higher than the average starting price of 116.67 euros.
- The estimated price for this auction is 250 euros, suggesting that there are expectations for the coin to reach a higher price.

4. Price Trends:
- In recent auctions, hammer prices have been increasing, especially for coins with similar conditions.

Based on these factors, an estimated maximum purchase price could be around 250-300 euros, considering that the coin has a condition of 80 and there has been growing interest in coins of this type. This also aligns with the most recent high hammer price of 245 euros.

Therefore, a reasonable maximum purchase price could be 300 euros.