Effects Pedal ????

I have been playing acoustic guitar now for a while, and since i wanted to get into electric i bought an epiphone special sg and a marshall amp (15 watt) not that big. but anyway im looking to buy some type of effects pedal, or something i can use to make multiple effects. I play alot of AC/DC, and black sabbath, and even some classic rock. I was wondering if anyone could suggest a pedal or effects thing that i could buy for less than 100 bux.

thanks