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

1. Starting price: 50 euros.
2. Average hammer price in the past: 110 euros.
3. Current condition: 70 (MBC-), which indicates a fairly good condition, although not the best.
4. Auction history: It has been auctioned 2 times in the past, with 1 sale and 1 no sale. This suggests that there is interest, but also that there may be limitations in demand.
5. Average starting price: 50 euros, indicating that the starting price has remained constant.

Given that the average hammer price in the past was 110 euros and considering that the current condition is 70, which is lower than the condition of the coins that reached that price, we could estimate a maximum purchase price that is lower than the previous average hammer price.

Taking all these factors into account, an estimated maximum purchase price could be between 80 and 100 euros. This reflects an interest in the coin, but also takes into account the condition and auction history.

Therefore, a reasonable estimated maximum purchase price would be 90 euros.