Updated spreadsheet.
https://app.box.com/s/l5h52g89trihff49f6nwNew top or bottom; $35
New set; $70
Two New sets; $130
(New: still has tag on it, clean, not faded, never been worn)
Then depending on the condition of the used ones, decrease the price necessary to match the value.
Probably something like this;
Like new top or bottom; $30
Like new set; $60
Two like new sets; $110
(Like new: no tag, clean, not faded)
Used top or bottom; $25
Used set; $50
Two used sets; $90
(Used: no tag, clean, little worn or faded on knees or elbows, no rips)
Worn or faded top or bottom; $20
Worn or faded set; $35
Two Worn or faded sets; $60
(Worn or Faded: no tag, combat dirty, possible missing button, slightly faded all around and worn)