Insulating a metal building

I have a 24*30 enclosed A-frame carport. Studs are 5' oc, (2 ⅛"* 2 ⅛ metal studs). 10' walls. Thinking about insulating it.
Is it worthwhile to only insulate 2" thick? I was thinking something would be better than nothing.
Foam board or bead board? If I use one of these two items, do I still need a vapor barrier? Or do they act as a vapor barrier?
Insulate Ceiling vs walls? Both would be ideal, will have to see how the finances go.
Spray insulation? What kind of finish does this have?
Use of the building: boat and utility trailer storage, work shop.
Temperature swings in this area: 0°f - 100°f. Those are the extremes, usually not sustainable for more than a week.

IMO...Expanding foam is the best, although not cheap. You can get DIY kits, that would allow you to do it in stages if necessary. there are video's on you tube showing the process.

But like you said any insulation is better than none at all....

If you have metal framing with metal skin you need a thermal break. Covering your inter skeleton with a 1" foam board then covering with wafer board will work nicely. Metal is 200 times more conductive of heat than wood