To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current starting price: 80 euros.
2. Coin condition: 70 (MBC-), which is an acceptable condition, but not excellent.
3. Auction history:
- It has been auctioned 7 times in the past, of which it has sold 4 times.
- The average starting price in previous auctions is 332.49 euros, and the average hammer price is 196.15 euros.
4. Previous prices:
- In 2012, it sold for 120 euros with a condition of 80.
- In 2016, it sold for 254.59 euros with a condition of 80.
- In 2022, it was estimated at a price of 475.55 euros with a condition of 85, although it did not sell.

Given that the current condition of the coin is 70, which is lower than the conditions of 80 and 85 from previous auctions, it is reasonable to expect that the hammer price will not reach the higher levels observed in the past.

However, the current starting price is 80 euros, suggesting that the seller has expectations for the coin to sell at a reasonable price.

Considering the price history and the current condition, an estimated maximum purchase price could be in the range of 100 to 150 euros. This is based on the fact that, although the condition is not the best, there is a history of hammer prices that suggests the coin has significant value.

Therefore, an estimated maximum purchase price could be 120 euros.