Marriott is offering points with the biggest bonus we’ve seen – you are effectively prepaying for stays at a discount.
A 60% bonus on purchased points, that began May 18, was set to end June 30. This has been extended to run through July 15. The best previous deal I’m aware of was a 50% bonus, though of course Marriott points aren’t worth as much as they used to be either. They’re willing to sell you points at a cost per point of $0.0078.