Price drops when more people buy

Pav Bhaji for only $6
Snoball price
$6   20% OFF
Regular price  $7.50
Units sold this month  53
Units sold last month  NA
Vada Pav (1 pc) for only $2.25
Snoball price
$2.25   20% OFF
Regular price  $3
Units sold this month  39
Units sold last month  NA
$10 Worth Coupon for only $8
Snoball price
$8   20% OFF
Regular price  $10
Units sold this month  22
Units sold last month  NA
$5 Worth Coupon for only $4
Snoball price
$4   20% OFF
Regular price  $5
Units sold this month  15
Units sold last month  NA