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 fetch higher prices.

2. Starting Price and Average Hammer Price: The starting price is 45 euros, and the average hammer price in previous auctions is 133.8 euros. This suggests that, in general, coins of this reference tend to sell for significantly higher prices than their starting price.

3. Sales History: The coin has been auctioned 66 times, of which 63 have been sold. This indicates good demand and a history of successful sales.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (70), we can see that they have reached hammer prices of up to 160 euros in the past.

5. Recent Trends: In the most recent auctions, hammer prices for coins of similar condition have varied, but some have reached prices of 140 euros or more.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 120 to 160 euros, considering that the average hammer price is 133.8 euros and that condition is a key factor.

Therefore, a reasonable estimated maximum purchase price could be 150 euros.