The fee for proofreading double spaced works with a 12-point font, one-inch margins and a 250 word average per page is usually between $2.00 and $4.00 per page depending on the amount of editing needed and the due date requested.  Basic legal transcript proofreading at 25 double spaced lines per page is 45 cents per page for a maximum one week turn around.  Shorter deadlines are more expensive and will be quoted as requested.