Rotation for printing should be possible in any of the software's used for printing. Simply3d definately handles this for me, Cura will too.

As for simple stuff, I like tinkercad.com and have been very sucessful making small items or manipulating things, even as complex as a stargate model. Others will have other ideas, including Fusion 360. Blender would not be my choice, it's more for complex 3d models with colors, textures and lighting - definately more than you need for 3d printing - but others will disagree. You'll eventually find what you need, just dig in and learn one.