These are in no particular order.
Apple cider vinegar. Mixed maybe one shot glass to a 12 ounce glass of water. Taste is horrid but it seems to work. Seems to help with congested head as well as phlegm.
Club soda. This works well. The issue is price. Having 2 1 liter jugs a day amounts to many dollars over a month. Also good for getting out clothes stains.
Baking soda. Easily the cheapest. On box costs under a dollar and lasts for 3 months. I use about 1/2 teaspoon in the am and again when I get home. Taste is bad but I mix with maybe 3 ounces of water and just gulp it. To be sure it will raise blood pressure but when you look at the amount of salt in a mcdonald's #3 combo the amount is a small fraction.
I will concede that eating a low purine diet helps a lot. For myself I voluntarily gave up paenut products and shrimp. I should probably eat more greens.