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

1. Starting price: 60 euros.
2. Coin condition: 30 (BC+), indicating that the coin has a relatively low state of preservation.
3. Auction history:
- In 2016, the coin was auctioned with a starting price of 40 euros and sold for 70 euros.
- In 2014, the starting price was 15 euros and it sold for 35 euros.
- In 2022, the starting price was 40 euros, with a final bid of 160 euros, but the condition in this case was 70, indicating that the coin was in better shape.

4. Average final price: 88.33 euros, suggesting that, in general, coins of this reference tend to sell for a price higher than the starting price.

Given that the condition of the current coin is 30, which is lower than that of the 2022 auction, it is likely that the final price will not reach the higher levels observed in that auction. However, considering the average final price and the auction history, an estimated maximum purchase price could be in a range between the starting price and the average final price.

Taking all these factors into account, an estimated maximum purchase price could be approximately 80-90 euros. This is based on the fact that, although the condition is not the best, the interest in the coin and the bidding history suggest that it could reach a reasonable price at auction.