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

1. Current Condition: The coin has a condition of 70 (MS-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions, we can see that:
- In past auctions, coins with a condition of 70 have reached hammer prices that varied, but generally ranged between 95 and 240 euros.
- The last auction with a condition of 70 had a hammer price of 240 euros.

3. Average Hammer Price: The average hammer price for this coin is 210.28 euros, indicating that, in general, buyers are willing to pay around this amount.

4. Starting Price and Average Starting Price: The current starting price is 90 euros, and the average starting price is 129.06 euros. This suggests that the starting price is reasonable and that there is potential for an increase in the hammer price.

5. Sales Trends: The coin has been auctioned 89 times, with a high sales percentage (85 out of 89). This indicates that there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be around 240 euros, as this is the highest recorded hammer price for a coin in similar condition. However, considering the average hammer price and sales trend, a range of 200 to 240 euros would be a reasonable target for a buyer interested in this coin.