Yeah, the cheaper ones don't keep the heat out like the proper ones do.
I have VKool on one of my cars and Titanium on the other. Titanium is a few hundred riyals cheaper than Vkool, but there isn't a difference.

Beware of fake tints called IamJhonson, because they are just standard tints with a sticker on them to make it look like they are the real thing. (IamJohnson)