Don`t use tapwater! Tapwater (and bottled water) has ions and impurities which includes constituents of copper, iron, calsium, and sodium, which can give your soaps DOS very quickly (Dreadded Orange Spots = oils become rancid and makes ugly orange spots on soaps. Smells icky, doesn`t look good, but thay are NOT harmfull, just not pleasant)
But you don`t
have to use destilled water either, as that for many people is very expensive and makes soaping a very expensive thing. I live in Norway, and here distilled water is VERY expensive. So I use
DeIonized water, which is water that has impurities and metals removed and becomes a perfectly cleaned water that is great for soapmaking, AND is inexpensive. If you have a car you may even have it on hand already (to fill your car battery when it needs a top-up) The general industry (perfume, manufacturing etc) use DeIonized water to prevent buildup of minerals in ecuipment etc, hence it is great for soapmaking too. I buy a big 4L jug at a time.
And some people use rainwater that they collect. It is more clean from the metals, but I don`t want to use that either as the rain will collect different types of pollution on the way down from the clouds, and I don`t want that in my soap.
And yes, you can use Beer, Aloe Vera juice, even pure 5% vinegar. But since I got a sense that you are very new to all of this and have only made a coupple of batches, I would NOT venture into those fluids just yet, as sugars in them will make for some strong reactions you may not be ready for when you are so inexperienced.
Just take your time, practice with water first, and then try other things and learn as much as you can, and you will be fine!
Good luck