Buck Boost Circuits
For buck boost circuits, I recommend working around something like the MC34063ABN. You can design a circuit just by following some equations found in the datasheet: http://opencircuitinstitute.org/content/buck-converter-component-calculator The chips are cheap, small, and work automatically
Also something to touch on is LDOs vs buck-boost: http://opencircuitinstitute.org/content/low-drop-out-regulators-vs-buck-converters