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 fetch higher prices.

2. Auction History:
- The average hammer price for similar coins has been 132 euros.
- In previous auctions, the hammer price has varied, but there are examples of coins with similar condition that have sold for prices exceeding 150 euros (for example, in 2018, a coin with a condition of 80 was sold for 180 euros).

3. Starting Price and Average Starting Price:
- The current starting price is 90 euros, which is above the average starting price of 80.48 euros, suggesting that the seller has higher expectations.

4. Sales Trends: The coin has been sold in 32 out of 35 auctions, indicating good demand.

5. Previous Prices:
- In recent auctions, the hammer price has been 150 euros or more for coins with similar conditions.

Based on these factors, an estimated maximum purchase price could be in the range of 150 to 180 euros, considering that the highest hammer price in the past for coins of similar condition has been 180 euros.

Therefore, a reasonable estimated maximum purchase price could be 170 euros. This allows for a margin for competition in the auction and aligns with historical hammer prices.