There are two very different types of exploitation, in my opinion. There was the exploitation from America, which mainly consisted of blaxsploitation, biker and gang films, and rape/revenge flicks. Then, there was the softcore sexploitation from Europe, with two of the most significant sub-genres being WIP (women in prison) and "nunsploitation" films.
If you're interested in the trailers from Grindhouse, and would like to see the films that inspired their makers, here's a partial list off the top of my head:
Machete - Ask xfearbefore about this one, as I've never been very big on American exploitation, save for the horror films (I only say this because some people classify the horror films that played in drive-ins and NYC grindhouse theaters in the 70s/80s as exploitation; I personally don't consider them to be exploitation films).
Thanksgiving - Although ostensibly gorier, Thanksgiving definitely takes it feel from the lesser-known American slashers of the early/mid-80s (e.g., The Prowler, The Mutilator, and The Burning). Also, you might want to check out Maniac and Nightmares in a Damaged Brain.
Don't - Hammer horror. I've never been a fan of Hammer films, but, some people swear by the stuff. If you like Dark Shadows and/or horror in Gothic settings, then you'll love Hammer films.
Werewolf Women of the SS - Definitely inspired by Nazisploitation, which is another particularly popular sub-genre of exploitation (I didn't list it beforehand as I'm not quite sure if it should be classified as American or European exploitation). If you're interested in this trailer, the two films to see would be Ilsa, She Wolf of the SS and The Beast In Heat.
Oh, and when I recommend these films, I'm assuming that you're 18. If you're not, then forget what I said (or, at least don't tell your parents where you got the recommendations from should they catch you).