It's complicated.
In addition to the named arrows w/ spine deflection specs which sell individually, Wal-Mart gets in boxes of un-named arrows (the box indicates Carbon Express) which have no markings (save for a sticker w/ a bar code) and come in two lengths, 29" and 31". This year the boxes are divided into 4 sections and one can also get camo arrows for $4 (plain are $3) and they've marked the boxes and stickers w/ a range of draw weights (inconsistently --- box says one thing, sticker another).
I bought half-a-dozen each last year and shot the 31" arrows until recently replacing them w/ Carbon Express Heritage 150s. The unmarked arrows were okay and I enjoyed shooting them, but when I made a spine tester of Lego bricks I found they had several different deflections, which explained why I was only grouping so well --- I'm doing much better w/ the CX Heritage 150s.