To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Current Condition: The coin has a condition rating of 70 (VF-), indicating that it is in acceptable condition, but not among the best qualities.

2. Auction History:
- The average hammer price in previous auctions is 99.5 euros.
- The last auction for this coin had a hammer price of 160 euros with a condition rating of 80, suggesting that there is a market willing to pay high prices for coins in better condition.
- In previous auctions, hammer prices have varied, but there are examples of sales exceeding 100 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price.
- The average starting price is 50.83 euros, indicating that auctioneers usually start with higher prices.

4. Demand and Supply: The coin has been auctioned 17 times, with a sell-through rate of 94% (16 out of 17), indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 120 to 160 euros, considering that the coin's condition is a limiting factor and that the market has shown a willingness to pay higher prices for coins in better condition.

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