First of all, I would HIGHLY recommend
Ginger Root. It's dirt cheap and it greatly helps with upset stomach, stomach pains, GI tract issues and other things. Just make sure you take it with plenty of water. It can sometimes break open in your esophagus and it's pretty painful if that happens. There's also
NOW Peppermint Gels. They're enteric coated so they open in your intestines, instead of your stomach, so it really gets to the root of any pain you might be having. It has ginger oil and fennel oil in there as well. Peppermint has been shown to stop intestinal spasms, so it can help alleviate pain from stomach issues.
Activated charcoal is another good supplement that really helps with bloating and gas. They give people activated charcoal in the ER when they've taken some kinds of poison, so it helps absorb a lot of negative stuff and it's really noticeable when you take it for gas/bloating and helps a lot. It's also another very cheap supplement.
As far as probiotics, I personally take
Nature's Way Probiotic Pearls Complete. I like these because they're made in Japan and have a very good coating and use patented blends of probiotics from major well known labs and universities. When you buy any regular probiotic in a capsule, you have no idea if it's been refrigerated all the way from the factory to the warehouse to you and so by then, half the probiotics are already dead. But with the pearls, they use a proprietary coating system to ensure that the probiotics survive in any sort of environment. Your other best bet is just to eat some yogurt.
Finally, if you have any sort of acid reflux or acid indigestion, I've made up my own special blend for that. I use 1/2 teaspoon of baking soda (sodium bicarbonate) and 1/2 teaspoon
potassium bicarbonate. That help keeps your salt/potassium levels balanced, and the potassium bicarbonate helps you burp, so that acid indigestion will be gone in seconds after you mix it in a 4oz cup of water and stir it until it's clear.
Hope that helps!
-SS