Does the trick

I received this 3.4 oz bottle in an Ipsy bag about 2 years ago. I use a pea size amount every couple days (whenever I wash my hair) as directed and still have about half a bottle left. I have very thin hair and therefore have a problem with serums, etc weighing down my hair or causing it to look greasy. This is light weight and doesn't cause any of those problems. I do feel it protects my hair from blowdryers/straighteners. My hair looks shiny and smooth when it's done.
I recently found this again at Winners for like $8 and it now comes in a spray bottle which is convenient.

It Hair Care 12-in-One Leave In Treatment is awesome! It literally does 12 things! I apply about a dime sized amount to my thick, shoulder length hair while it's still damp. I work it all over my hair with my fingers first and then I gently comb thru my hair with a wide toothed comb to make sure it's all evenly distributed. Once my hair is dry, it is soft, smooth, shiny and has no frizz or fly aways! And it also smells great! I would totally recommend this product!

I have been using this for a while now and I think it's great. It leaves no residue in my hair (yet), my hair is soft and bouncy. I love that it says it will protect my hair from heat up to 450 degrees, which is great. It smells very nice and light of something I can't put my finger on. Floral maybe? I will be buying this again, I haven't found a thing to complain about yet.