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

1. Coin Condition: The coin has a condition rating of 95 (EBC+), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price and Previous Prices: The current starting price is 70 euros, and the average hammer price in previous auctions is 123.2 euros. This suggests that, in general, coins of this reference tend to sell for a significantly higher price than their starting price.

3. Auction History: The coin has been auctioned 22 times, of which 20 have resulted in sales. This indicates good demand and consistent interest in this coin.

4. Previous Hammer Prices: Looking at previous hammer prices, we can see that they have varied, but there are several examples where the hammer price has exceeded 100 euros, even reaching up to 170 euros in some cases.

5. Recent Trends: In the most recent auctions, hammer prices have ranged from 80 to 160 euros, which also suggests that there is potential for a higher hammer price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be in the range of 130 to 160 euros, given its condition and the history of hammer prices. This aligns with the average hammer price and the trends observed in previous auctions.

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