This is an affiliate. The coupon code is 10TRYSOYLENT and can be used directly without visiting the site.
What ever that listing was it is not one I would use, unless it is new Soylent doesn't come in vanilla, except the Cafe version.
These are the link with Amazon setup, for prime, subscribe and save and 20% off first order coupon.
Cafe varieties https://www.amazon.com/dp/B01IRFB0G2/
Original varieties https://www.amazon.com/dp/B01EUEIL3E/