Kickstarter/GoFundMe type "tiers" for purchases?

Site URL: https://plane-flatworm-ennl.squarespace.com/

Building a website for a client and they want tiered reward options for purchases - sort of like Kickstarter or Indiegogo. Hard to explain, but I'm not sure if it is possible on Squarespace commerce. Here is a link to a site that offers something similar, but my client want to offer a further step post-purchase, something like:

• if you buy a $25 product, you can opt in to get a free sticker.
• if  you buy a $50 product, you can opt in to get a free shirt.
• if you buy a $100 product, you can opt in to get a free sweater.
• etc.

Is this possible? They want that option available through a Squarespace product purchase, and at the point of purchase a customer can check if they would like to enter their address/info to receive the "free" promo item that matches their price point.