I've been asked a lot what is a good price for vinyl. You should not pay more than .50 a square foot for regular outdoor/craft vinyl (before shipping).
Rolls come in different sizes and widths, but calculate it per square foot so you can compare apples to apples.
To calculate:take width in inches x length in inches then divide by 144 to get the total square feet
so a 19" roll at 5 yards is 19 x 5 x 36(There are 5 yards and each yard is 36 inches) = 3420 divide by 144 this is 23.75 square feet - so you should pay $12.00 or less.
Also don't forget to add in shipping to get the real price, shipping prices vary and can add a lot.
Good luck and have fun!