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 of 70 (VF-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for similar coins in the past is 173.17 euros.
- The condition of the coins that have been sold in the past varies, but many of them have a condition of 80 or higher, indicating that the coin in question might be in a lower price range due to its condition.

3. Previous Hammer Prices:
- In previous auctions, the hammer prices for coins with similar conditions (70-80) have ranged between 40 and 145 euros, depending on demand and other factors.

4. Starting Price and Average Starting Price:
- The current starting price is 30 euros, and the average starting price is 78.39 euros. This suggests that there is considerable room for the hammer price to be higher.

5. Recent Trends: In the most recent auctions, hammer prices have been relatively high, which could indicate an increase in demand.

Based on these factors, an estimated maximum purchase price could be in the range of 100 to 130 euros. This is based on the historical hammer prices for coins of similar condition and the current market context. However, since condition is a limiting factor, it is wise not to exceed 130 euros to avoid overpaying.