Soy-free protein powders (or shakes, you didn't limit to isolate):

https://www.amazon.com/NATURELO-Plant-Protein-Powder-Vanilla/dp/B09K29LFJV/

https://www.amazon.com/NATURELO-Plant-Protein-Powder-Chocolate/dp/B09K2GS2KQ/

https://www.amazon.com/Less-Naked-Whey-Vanilla-Protein/dp/B0787RNSPQ/

https://www.amazon.com/Less-Naked-Whey-Chocolate-Protein/dp/B0787S4YN1/

https://www.amazon.com/PLANTFUSION-Creamy-Vanilla-Inspire-Women/dp/B081MTQYJM/

https://www.amazon.com/Bulksupplements-Pea-Protein-Powder-grams/dp/B00RPMMFYU/

https://www.amazon.com/Premier-Protein-Whey-Powder-Vanilla/dp/B06ZZ3PJQD/

https://www.amazon.com/NutraBio-Protein-Isolate-Chocolate-Pounds/dp/B00DP3QMYW/

https://www.amazon.com/Ora-Organic-Vegan-Protein-Powder/dp/B071GSFY4F/

https://www.amazon.com/Premier-Protein-Plant-Based-Ingredients-Servings/dp/B0BVWN84GR/

https://www.amazon.com/Naked-Vegan-Mass-Artificial-Ingredients/dp/B07XTQKYG1/ref

...

Also, three soy-free ideas that compare with most protein shakes:

(All of these work out to around 3 cents/gram protein)

Liquid Egg Whites - purchased by the quart, almost all of the calories are from protein.

Spirulina - %~60 protein and lots of other benefits, especially for weight loss, tablets and powder

14.75oz can of Wild Alaskan Pink Salmon - around %65 of calories from protein, one can is 90g protein, 7g Omega 3 + astaxanthin, phosphorus, calcium, selenium, Vitamin D

Premier Protein Whey Protein Powder, Vanilla, Packaging may Vary (17 Servings), 28 oz https://www.amazon.com/dp/B06ZZ3PJQD/ref=cm_sw_r_cp_api_i_m8n8EbGDSAC26

Here’s a vanilla I’ve gotten that tastes amazing (I’ve used it for some of his stuff) that’s super cheap right now