Based on the provided data, we can observe that the coin in question has had an average starting price of 57.75 euros in previous auctions, with an average closing price of 42.83 euros. The coin's condition is described as 70 (MBC-).

Additionally, several auctions have been conducted in the past with varying starting and estimated prices. Below is a summary of the previous prices of the coin:

- Auction Date: 2020-12-15, Starting Price: 40, Estimated Price: 50, Closing Price: 45, Condition Value: 75
- Auction Date: 2020-09-17, Starting Price: 18, Estimated Price: 30, Closing Price: 35, Condition Value: 75
- ...

Given that the coin's condition is in an acceptable state (70 MBC-) and considering the previous prices of similar auctions, as well as the average starting and closing prices, we could estimate a maximum purchase price of around 50-60 euros for this coin in the next auction. It is important to note that the final price may vary depending on demand and other factors at the auction.