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

1. Condition: The coin has a condition of 70 (MS-), indicating that it is in acceptable shape, but not of the highest quality. This can influence the price, as coins in better condition tend to fetch higher prices.

2. Previous auction prices: By looking at the hammer prices of coins with a similar condition (70), we can see that they have ranged between 130 and 225 euros in previous auctions. For example, in several auctions, coins with a condition of 70 have sold for prices like 170, 220, and 190 euros.

3. Average hammer price: The average hammer price for this coin is 170.74 euros, which provides a good reference for the expected price.

4. Starting price: The starting price of the current auction is 140 euros, which is reasonable and may attract bidders.

5. Market trends: Since the coin has been auctioned 98 times and has sold 90 times, there is good demand and a history of successful sales, which may indicate that interest in this coin is strong.

Based on these factors, an estimated maximum purchase price could be around 200 euros. This price reflects a balance between the coin's condition, previous hammer prices, and market trends. However, it is important to keep in mind that the final price may vary depending on the competition in the auction and the interest of other bidders.