I don't use Argan oil but I do use a hair oil. I don't think it needs to actually be Argan oil to make a difference to your hair
. Avon has been raved about in this thread but actually has a minuscule amount of Argan oil in it (see here
I received L'Oreal's Mythic Oil in a Glossybox about a year ago but never really used it as I hate having oil on my hands. But more recently my hair has been in a bad condition so I've started using it. It's really made a difference and I've nearly used it up. I've just bought their Extraordinary Oil so I can't wait to try that out.
My hair is naturally very greasy but it's been no more greasy using an oil.
No you don't need to use argan specifically, I actually think coconut oil has more conditioning properties than argan oil, but that's just in my experience. This is why I use a blend of oils, so I can get use the best of the best oils in one hit!