Can someone help me cropping a photo... nothing too complicated.?

Ladies and gents... I need help cropping one photo into another. Its really simple I don't need it looking amazing, it can be some what of poor quality but using Paint and Microsoft Publisher isn't cutting it (no pun intended.) Can someone direct me to some good/free software or maybe even just do it for me... Like I said... It doesn't have to be amazing quality just something simple. Either one would be great! Thanks!