To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in fairly good shape, but not among the best qualities.

2. Auction History:
- The average hammer price for similar coins is 634.71 euros.
- In the past, coins with a similar condition (75) have sold for prices that varied significantly, ranging from 60 euros to 2900 euros, depending on demand and other factors.

3. Starting Price: The starting price is 120 euros, which may be a good indicator of the seller's expectations.

4. Price Trends:
- In previous auctions, coins with a condition of 75 have had hammer prices ranging from 60 to 220 euros on several occasions.
- The highest auction price for a coin with a condition of 75 was 2900 euros, but this appears to be an exceptional case.

5. Analysis of Previous Sales:
- Out of the 17 times it has been auctioned, 14 have been sold, indicating a good sales rate.
- The average starting price of 362.01 euros suggests that sellers expect to achieve higher prices than the current starting price.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 200 to 300 euros, considering that the condition is good but not exceptional, and that the price history shows variability. A price of 250 euros could be a reasonable target, as it falls in the middle of this range and is consistent with the trends observed in previous auctions.