Still need to check Lowes for a couple things where HD didn't have precisely what I wanted. Numbers in parentheses are how many I believe I need.
Floor frame & Joists: 10-ft 1x2 clear cedar -- $4.55 ea (5)
Subfloor: 5/8" 4x8 plywood -- $17.59/sh or 15/32" 4x8 plywood -- $12.88/sh (2)
Frame screws: #7 x 1 5/8" stainless steel square drive -- $15.95/box (1)
Insulation: 3/4" 4x8 white polystyrene (HD only has pink Foamular in 1" or thicker, need to check Lowes for 3/4") -- $8.44/sh (2)
Insulation Screws: #8 x 1 1/4" Modified Truss Head -- $4.46/box (1)
Insulation Washers: 3/16" x 1 1/4" fender washers -- $13.50/box (1)
Adhesive: Gorilla Glue 18 oz. bottle -- $18.97 (1)
Waterproofer: Henry Wet Patch Roof Cement 3.5 gallon bucket (check Lowes for BlackJack Emulsion Roof Coat) -- $34.50 (1)
Looks like I should be able to build the floor for around $160.

Any comments are welcome.