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

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

2. Auction History:
- The average hammer price for this coin is 295.85 euros.
- In previous auctions, hammer prices have varied, but there are examples of sales that have reached up to 8000 euros in exceptional conditions (such as in the auction on 2022-05-23).

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, which is quite low compared to the average hammer price.
- The average starting price is 87.66 euros, indicating that similar coins usually start auctioning at higher prices.

4. Recent Trends:
- In the most recent auctions, hammer prices have shown an increase, which could indicate a rising trend in interest for this coin.

5. Comparison with Similar Conditions:
- Coins with similar conditions (70) have had hammer prices that vary, but are generally above the current starting price.

Based on these factors, an estimated maximum purchase price could be in the range of 200 to 300 euros, considering that the condition is good and that the hammer price history suggests it could reach a higher value at auction. However, since the starting price is low, there may be an opportunity to purchase at a more accessible price.

Therefore, a reasonable maximum purchase price could be 250 euros.