i dont like tea tree because it made my hair grease up. greaselocks? so i would think only use that stuff if u have really dry hair.
updated by @blair-joseph-ripperger: 07/23/15 05:46:58PM
completely depends on the oil. Sandlewood can cost between $15-$45 for .5 fl.oz. Peppermint around $6-$9. Tea tree is around that range too. Sandlewood is usually one of, if not the most expensive. Most of the ones you're looking for are anywhere between $6 and $11
.5 oz is actually a decent amount, so don't get turned off because it sounds so small. You can get a few hundred drops out of each bottle