SPG is offering up to a 50% off the regular purchase price of Starpoints. This is the highest bonus they have every offered, but it is a targeted offer and the discount will vary.
Buying points usually doesn’t make sense, unless you need some extra points to reach a redemption. In this case if you have the 50% off offer, you will be buying Starpoints at ~1.7 cents a piece and considering that you can get well over 2 cents in value usually, it should make sense to some.
To check what bonus you get, go here and log in with your info. You should see 25%, 30%, 35% or 50% off. Minimum purchase of 5,000 Starpoints required to get the offer shown.
If you maximize this offer, you can get 30,000 Starpoints for $525 after the 50% discount. If you use an Amex SPG card to purchase Starpoints, you will earn 2x Starpoints per dollar. so you will get an extra 1050 Starpoints. So you’ll be purchasing points at ~1.7Cents. Go through a portal and you can lower that price even further.
Keep in mind that you can also transfer Starpoints to Marriot, 1:3.
Your account may receive up to a maximum of 30,000 Starpoints per account per calendar year, whether purchased by yourself or received as a gift from another member. However, you may purchase as a gift for other accounts, as many Starpoints as desired. Each gift recipient can receive up to 30,000 Starpoints per calendar year.