Underlayment and valley recommendations on 12/12 dimensional shingle

Should I ice and water the whole thing?  Use a synthetic peel and stick product in the field? Regular paper in the field?

Any thoughts on open vs closed valley, metal vs no metal in the valley?

The house is in a fairly poor neighborhood so I don't need a Caddillac system.  It's 30 squars, underlayment material cost will make a difference.

Thanks for the help!