First, I would find a copy of The Rigger's Apprentice by Brion Toss and read his advice about rope selection and the tradeoffs involved. Even if you have to buy this book new, you'll pay for it many times over based on this one section alone. For such a boat, I'd probably be happy with 3-strand polyester for most of my running rigging, but I might spring for some regatta braid for the sheets (just for the nice hand.) As a plus, splicing is super easy with 3-strand.
Here's some sample prices (though you might get a better rate if you could get a whole reel.) NOTE: I am not implying that these are the right sizes for you, nor that these lines have the same breaking strengths just because they're the same diameter. Read a rigging guide or the book above to size your lines properly.
New England Rope 3-stand polyester 1/4": $0.25/ft
Sta-Set polyester 1/4": $0.43/ft
Sta-Set X polyester 1/4": $0.51/ft
My boat is a 32' marconi-rigged cruising cutter. For my purposes, I like having regatta braid sheets, Sta-Set halyards, and 3-strand for a lot of other lines. My 10' sailing dinghy only has 3-strand polyester on its sprit sail rig. I have no use for Sta-Set X, but then again, I'm not a racer
