What are some quick and affordable insulation solutions for a shed?
edited after picture added to question 

It's tough to get a big shed like that warm when everything's cold.  You can heat up the air quickly, but the slab, the walls, the contents all soak up that heat so it takes a while to warm up.  That happens even with insulation, although it probably won't be as cold first thing in the morning if it's insulated.  

I'd probably go across the collar ties so you have a little less space to heat and a good area above for ventilation.  You'll want to cut in a small gable vent at either end.  I'd say I'd use foam board on the ceiling, it will be easier to deal with than bats.  To use bats you'd have to add collar ties.  The foam board will leave some space so air can flow up from the eves over the insulation to the space above the rafter ties and out the gable vents.  

It will be a lot cheaper to use bats on the walls.  Left uncovered they'll be prone to tears.  You could cover with pegboard halfway down and hardboard from the pegboard down to the floor.  

Not really a cheap project unfortunately, it adds up to a few bucks any way you slice it.  You could buy one of those battery powered jackets ...