Where to buy sweat pants? 10 points!?

my friend has these black sweatpants that are baggy but at the end they have that elastic so it's tight around your ankles..if you know what i mean. but we're both skinny 13 year olds so I need a tight waist. do you know where i can buy sweatpants like these? btw i'm only like 90 lbs if that helps. just not huge ones. And please don't say victoria's secret, they can't be over 20 dollars a pair!