Any formula your doc orders can be covered through WIC. You just have to find the local tribe or state WIC office that carries it. We had to do the Osage tribal WIC for my grandson's formula. All the other grand kids did state WIC. His formula was only carried by the tribe. It was actually better than the state WIC. They did name brands and offered more options.
As for your doc saying to put cereal in a 2 week old babies formula, that doc is an idiot. Find a new doc.
A baby cannot digest cereal until they are very very close to 6 months old. Your baby was feeling gut wrenching pain with a substance similar to concrete in her tummy and no way of getting it out for hours and hours.
A baby cannot process any sort of food until much older. Do talk find some other way of getting samples though so you can try the formula's without buying a bunch of kinds.
I know that Nutragen is expensive but if she does well on it for now then keep her on it until her tummy matures some. After a few months you may be able to go back to a different formula.
Try putting a few gas drops in the bottle before adding the water. After than add the water then powder. Swish it around, not shaking it. Then let it sit for a couple of minutes. This should get all the bubbles out of the mixture and as she eats the meds will prevent gas from forming in her tummy.
She may need to see a specialist to help you figure out what is going on. My friends son did the reflux test at a young age and his stomach was re-flexing the whole test. They put him on liquid Reglan before each bottle and he was wonderful after that. It relaxes the stomach muscles so the tummy empties much faster so more formula goes into the intestines where it gets used for food.