A Meta-Analysis of 30 COVID-19 Early Treatments from 68 Countries
The following website (https://c19early.com/) provides a great summary and meta-analysis of COVID treatment studies, including those approved for clinical use, in 68 countries. They include treatment cost as well.
Please note that treatments are stage-dependent based on how early or late in the infection (viral replication) cycle the intervention is made.
Some low-cost but surprisingly powerful treatments include: Curcumin (turmeric), Melatonin, Vitamins A & D, Zinc, Quercetin, Ivermectin, HydroxyCQ, Povidone-Iodine (which I already discussed in my other article about anti-viral nasal irrigation HERE), and Probiotics (like those in fermented food).