To estimate a maximum purchase price for the coin with a grade of 80 (MBC+), we can analyze historical data from previous auctions of coins with similar grades and their hammer prices.

1. Hammer Price Analysis:
- In previous auctions, coins with a grade of 80 (MBC+) have had varying hammer prices. For example:
- In the auction on 2023-01-18, a coin with a grade of 80 was sold for 200 euros.
- In the auction on 2022-10-18, a coin with a grade of 80 was sold for 116 euros.
- In the auction on 2022-11-29, a coin with a grade of 90 was sold for 115 euros.

2. Comparison with Starting Prices and Estimates:
- The starting price of the coin in question is 110 euros, and the average hammer price for similar coins is 96.38 euros.
- The average starting price is 54.36 euros, indicating that the current starting price is relatively high compared to the average.

3. Maximum Price Estimation:
- Given that the coin's grade is 80 (MBC+), and considering that previous auctions have reached hammer prices of up to 200 euros for similar grades, a reasonable maximum purchase price could be in the range of 150 to 200 euros, depending on the demand at the auction.

Conclusion: An estimated maximum purchase price for the coin with a grade of 80 (MBC+) could be 150 euros. This is based on the analysis of previous hammer prices and the coin's grade.