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

1. Current Condition: The coin has a condition of 70 (VF-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price of similar coins in the past has been 297.11 euros.
- Previous auctions of this coin have shown hammer prices that varied, but some have reached up to 650 euros in superior conditions (such as in the case of condition 95).

3. Starting Price and Estimates:
- The current starting price is 300 euros, which is slightly higher than the average starting price of 241.49 euros.
- The estimated price for this auction is 350 euros, suggesting that there are expectations for the coin to sell at a price higher than the starting price.

4. Sales Trends: The coin has been sold in 47 out of 50 auctions, indicating high demand and a good sales history.

5. Comparison with Previous Prices:
- In previous auctions, coins with similar conditions have had hammer prices ranging from 240 to 440 euros, depending on the condition and other factors.

Based on this data, an estimated maximum purchase price could be in the range of 400 to 450 euros, considering that the condition of 70 (VF-) is a limiting factor, but that the sales history and demand are favorable.

Therefore, a reasonable maximum purchase price could be 450 euros.