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

1. Current starting price: 350 euros.
2. Coin condition: 70 (MBC-), indicating acceptable but not excellent condition.
3. Auction history: The coin has been auctioned 9 times, of which it has sold 8 times. This indicates good demand.
4. Previous hammer prices: The hammer prices have varied, but the highest was 440 euros in 2016, and the most recent was 400 euros in 2024.

Given that the current condition of the coin is 70, which is lower than the conditions of some coins that have sold in the past (for example, 85 and 80), it is reasonable to expect that the hammer price will not exceed the highest prices from previous auctions.

### Analysis of previous prices:
- Average hammer price: 368.75 euros.
- Maximum hammer price: 440 euros (in 2016).
- Most recent hammer price: 400 euros (in 2024).

### Estimation:
Since the current condition is lower than the conditions of coins that have sold for higher prices, and considering the starting price of 350 euros, an estimated maximum purchase price could be in a range between the average hammer price and the most recent hammer price.

Therefore, an estimated maximum purchase price could be approximately 380-400 euros. This reflects an expectation that, although the coin has good demand, its condition limits the price that buyers would be willing to pay.