I've been using Morocanoil for about a year and I tried something from Boots once which was recommended on here and was half the price. It didn't even come near to what Moroccanoil did for my hair. I gave it away after a couple of tries and bought another bottle of Moroccanoil. It is £30, but it lasts forever. It might be worth signing up for Buyapowa updates. That's the only place I've ever seen it cheaper - in fact, since I was the first person to sign up for the buy, I got it for free!
My mil bought me some for xmas as I couldn't justify the price. It is absolutely fantastic and worth the extra imo. You hardly need any and the difference it has made to my hair is unbelievable. I have very frizzy dry curly hair that most conditioners don't touch. I suppose if you don't have extreme problems with your hair and are youngish you may not need the expensive stuff though, not sure I would have done 10 years ago. Hope this helps.