To estimate a maximum purchase price for the coin with a grade of 70 (MS-), we can analyze historical data and price trends.

1. Data from previous auctions:
- The coin has been auctioned 205 times, of which it has sold 180 times.
- The average hammer price is 58.59 euros.
- In previous auctions, hammer prices for coins with a similar grade (70) have varied, but they have generally remained in a range of 14 to 25 euros in recent auctions.

2. Price trends:
- In recent auctions, hammer prices for coins with a grade of 70 have been around 20-25 euros.
- The last auction of a coin with a grade of 70 had a hammer price of 22 euros.

3. Additional considerations:
- The starting price is 15 euros, indicating that the seller expects a higher hammer price.
- Given that there are 4 auctions scheduled in the coming days, this could increase competition and, therefore, the price.

Estimation of the maximum purchase price:
Based on the above information, a reasonable maximum purchase price for the coin with a grade of 70 (MS-) could be in the range of 25 to 30 euros. This takes into account the average hammer price and the possibility that competition in the auction may drive up the price.