Dove sensitive skin soap - not the regular bar - has been a wonderful find for me. At Costco, I got 8 bars/$16, so $2 a bar.
The soap should always be followed up with lotion, and for that, I think Cetaphil is the best I've used. Very gentle, and again, reasonable at Costco for 2 big bottles that last several months.
Cetaphil soap is also good - don't get the anti-bacterial kind, just the regular, and the bar lasts longer than the liquid - but after years of exclusively using the more expensive Cetaphil, I have been very happy with the results from the Dove.
I have SUPER dry skin, so I tend to baby it. If you want a combo of gentle body wash AND shampoo, you can always try Johnson & Johnson's Baby Wash, which is available... wait for it... at Costco in enormous bottles at a very reasonable price. Try a small bottle first to see if it works well for you.
As madgeylou says, put the lotion or oil on when your skin is still slightly damp. It creates a barrier and helps keep your skin moisturized longer.
The best money I EVER spent was to put a whole-house humidifier on our furnace. It keeps the humidity level in the house at about 45% all winter long. My skin doesn't crack, our sinuses stay in good shape, and we can keep the thermostat lower because the moist air is more comfortable than dry air.