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

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

2. Auction History:
- The average hammer price for this coin in the past is 429.87 euros.
- The average starting price is 183.01 euros.
- It has been auctioned 89 times, of which it has sold 66 times, indicating good demand.

3. Previous Prices:
- In previous auctions, hammer prices for coins with similar conditions (75) have varied, but there are examples of auctions reaching up to 700 euros (as in 2012).
- There are also examples of lower hammer prices, but in general, prices tend to be higher for conditions of 75 or above.

4. Recent Trends:
- In the most recent auctions, hammer prices have been in the range of 70 to 480 euros for similar conditions.

Based on this data, an estimated maximum purchase price for this coin could be in the range of 400 to 600 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.

Therefore, a reasonable maximum purchase price could be 500 euros.