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

1. Coin Condition: The coin has a condition of 70 (MS-), indicating that it is in acceptable condition, but not of the highest quality. This will affect the maximum price that can be offered.

2. Auction History:
- The average hammer price for similar coins has been 203.77 euros.
- In previous auctions, coins with a similar condition (70) have reached hammer prices that varied, but some examples are:
- 110 euros (2020-09-17)
- 85 euros (2020-07-02)
- 130 euros (2022-10-18)
- 180 euros (2023-01-31)

3. Starting Price and Estimates:
- The current starting price is 30 euros, which is quite low compared to previous hammer prices.
- The average starting price for similar coins is 125.58 euros, suggesting that the current starting price could be a good opportunity.

4. Recent Trends: Recent auctions show that there is a consistent interest in coins of this reference, and the hammer prices have been relatively high compared to the starting price.

Based on these factors, an estimated maximum purchase price for this coin could be between 150 and 200 euros, considering that the condition is a limiting factor and that interest in the coin may influence the final price.

Therefore, a reasonable maximum purchase price could be 180 euros.