To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

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 similar coins has been 64.55 euros.
- In previous auctions, hammer prices have varied, with some reaching up to 270 euros in similar or better conditions.
- The last auction of a coin with a similar condition (80) had a hammer price of 40 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, and the average starting price has been 37.97 euros.

4. Sales Trends: The coin has been auctioned 70 times, of which 63 have sold, indicating good demand.

5. Future Projections: There are 3 auctions scheduled in the coming days, which may influence competition and interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering that the condition is good and that the price history shows that coins in similar conditions have reached higher prices in the past. However, since the starting price is 30 euros, it is likely that the hammer price will not significantly exceed the previous average hammer price.

Therefore, a reasonable maximum purchase price could be 80 euros.