Prices are more for plus sizes.  The 1x is $115
The bust is measured from underarm seam to underarm seam across the front.  Double to get the circumference. The length is measured straight down to the hem in the front and back.
This top runs true to size.
X-Small: Bust is 19" (38" around), front length is 23", back length is 28"
Small:  Bust is 20" (40" around), front length is 23.5", back length is 28.5"
Medium:  Bust is 21" (42" around), front length is 24", back length is 29"
X-Large:  Bust is 24.5" (49" around), front length is 26", back length is 30"
1X:  Bust is 26" (52 around), front length is 26.5", back length is 21"