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 75 (MBC), which indicates that it is in an acceptable state, but not among the best conditions. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The average hammer price for similar coins has been 309.27 euros.
- In previous auctions, we have seen hammer prices that varied significantly, ranging from 72 euros to 1000 euros, depending on the condition and other factors.
- The last auction of a coin with a similar condition (75) had a hammer price of 210 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 100 euros, which is lower than the average starting price of 136.38 euros. This suggests that there may be room for the hammer price to be higher.

4. Sales Trends: The coin has been sold in 31 out of 33 auctions, indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 250 to 350 euros, considering that the average hammer price is 309.27 euros and that the coin's condition is a limiting factor. A price of 300 euros could be a reasonable target, given the auction history and current condition.