Lufthansa’s Miles&More program sells miles in an unusual way, disguising them as a bundle even though the other components don’t make much sense.

You can purchase up to 250,000 miles in a calendar year using bundles, excluding the bonus. The September offer is valid through the end of the month and includes up to a 50% bonus (likely only available to members who haven’t previously purchased these).
A great solo travel tip spotted this week on LoyaltyLobby.