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

1. Condition of the current coin: 80 (MBC+).
2. Hammer prices of coins with similar conditions:
- 80 (MBC+):
- 2022-05-10: €35
- 2022-09-20: (no recorded auction)
- 2024-04-22: €45
- 2024-12-18: €40
- 75 (MBC):
- 2021-11-11: €35 and €30
- 2022-02-22: €45
- 2019-07-03: €33
- 85 (MBC+):
- 2019-07-03: €33 (although it is slightly higher, it may be relevant).

3. Price analysis:
- The average hammer price for coins with a condition of 80 seems to be in the range of €35 to €45.
- The average starting price is €29.15, indicating that the market is willing to start bidding in that range.

4. Estimation:
- Given that the condition of the coin is 80 and considering previous hammer prices, a reasonable maximum purchase price could be in the range of €45 to €50.

Therefore, an estimated maximum purchase price for this coin could be €45.