To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the conditions of the auctioned coins.

1. Starting price: 350 euros.
2. Times it has been auctioned in the past: 92.
3. Times it has sold in the past: 84.
4. Average hammer price: 167.6 euros.
5. Previous prices for this coin: The highest hammer prices have been 2000 euros (in 2019) and 370 euros (in 2019), with other hammer prices ranging from 80 to 625 euros in different auctions.

Since there is no information about the condition of the current coin, it is difficult to make an accurate estimate. However, we can observe that:

- Coins with higher conditions (95) have reached significantly higher hammer prices (up to 2000 euros).
- The majority of hammer prices are in the range of 80 to 370 euros, with an average of 167.6 euros.

Given that the starting price is 350 euros, which is relatively high compared to the average hammer price, and considering that there is no information on the condition of the coin, an estimated maximum purchase price could be slightly lower than the starting price, given the risk of not reaching that value at auction.

Estimated maximum purchase price: 300 euros.

This price reflects a balance between the starting price and previous hammer prices, taking into account the lack of information about the current condition.