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 shape, but not among the best qualities. This generally affects the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The coin has been auctioned 29 times, of which it has sold 22 times. This indicates good demand.
- The average hammer price in previous auctions is 27.82 euros, providing a reference point.
- In recent auctions, the hammer price has varied, but it has been observed that coins in similar conditions (around 80) have reached hammer prices of up to 70 euros.

3. Starting Price and Estimates:
- The current starting price is 30 euros, which is slightly higher than the average starting price of 21.04 euros. This may indicate that the seller has higher expectations due to demand or condition.
- The estimated price for this auction is 60 euros, suggesting that the seller anticipates good interest.

4. Price Trends:
- In previous auctions, hammer prices have fluctuated, but generally, coins with conditions of 80 or higher have reached higher prices. Given that this coin has a condition of 70, it is reasonable to expect that the hammer price will not significantly exceed the average.

Based on these factors, an estimated maximum purchase price could be between 40 and 50 euros. This is based on the price history, current condition, and price trends in previous auctions. However, since the starting price is 30 euros, it is possible that some bidders may be willing to pay a little more, but I would not expect the hammer price to exceed 50 euros on this occasion.