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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape.

2. Previous Prices:
- The average hammer price for this coin has been 226.81 euros.
- In previous auctions, hammer prices have varied significantly, ranging from 40 euros to 2000 euros, depending on the condition and demand at that time.

3. Price Trends:
- In the most recent auctions, hammer prices for coins with similar condition (80) have been in the range of 110 to 170 euros.
- The 2018 auction with a hammer price of 2000 euros appears to be an exceptional case, possibly due to very high demand or a specific event.

4. Starting Price and Estimates:
- The starting price is 70 euros, which is reasonable given the average starting price of 63.33 euros.
- The estimated price for this auction is 100 euros, suggesting that bidders may be willing to pay more than the starting price.

Based on this data, an estimated maximum purchase price could be in the range of 150 to 250 euros, considering that the condition is good and that the average hammer price has been significantly higher in the past. However, since the market can be volatile, it is advisable not to exceed 250 euros to avoid overpaying.

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