To estimate a maximum purchase price for the coin in question, let's consider several factors:

1. Current starting price: 19,000 euros.
2. Coin condition: 85 (ebc-), indicating good condition, although not the best.
3. Auction history:
- In 2017, the coin was auctioned with a starting price of 25,000 euros and sold for 33,000 euros.
- In 2021, although there was no starting price, it was estimated at 30,000 euros and sold for 32,000 euros, with a condition of 95, which is significantly better than the current one.

4. Average starting and final prices: The average starting price is 22,000 euros and the average final price is 32,500 euros.

Given that the current condition is lower than that of previous auctions, and considering that the current starting price is lower than previous starting and final prices, we can estimate a maximum purchase price.

Taking all these factors into account, a reasonable maximum purchase price could be between the average final price (32,500 euros) and the estimated price from previous auctions (30,000 euros).

Therefore, an estimated maximum purchase price could be around 30,000 to 32,000 euros. This reflects a balance between the current condition and the price history of the coin.