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

1. Current Condition: The coin has a condition of 70 (VF-), which indicates that it is in acceptable shape, but not of high quality. This generally affects the price, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for similar coins has been 497.52 euros.
- In previous auctions, coins with a similar condition (70) have had hammer prices that varied, but some examples are:
- 280 euros (2020-12-15)
- 220 euros (2019-03-14)
- 210 euros (2022-10-17)
- The trend shows that coins with a condition of 70 have reached hammer prices in the range of 150 to 280 euros in recent auctions.

3. Starting Price and Average Starting Price:
- The current starting price is 125 euros, which is relatively low compared to the average hammer price.
- The average starting price for similar coins is 280.37 euros.

4. Demand and Auction Frequency: The coin has been auctioned 99 times, with a high sales percentage (88 out of 99). This suggests that there is consistent interest in this coin, which may increase its value at auction.

Based on these factors, an estimated maximum purchase price could be in the range of 250 to 300 euros, considering that the condition is a limiting factor and that the starting price is relatively low. Therefore, a reasonable maximum purchase price could be 300 euros.