Given that the coin has a grade of 70 (MBC-), indicating good quality, and considering that it is being auctioned for the first time, the starting price is set at 350 euros.

Without historical sales data for this reference, it is difficult to establish an exact hammer price. However, in auctions, it is common for the final price to be between 1.5 and 2 times the starting price, especially for coins in good condition.

Therefore, an estimated maximum purchase price could be in the range of 525 to 700 euros, depending on the interest of collectors and competition in the auction.

I would recommend keeping an eye on the auction and considering these factors when setting your bidding limit.