B..
For a 3 year old, you could make it cheaply. However, it wouldn't be more then a dollar or two cheaper. Might as well save the time, at that point. UNLESS, you want a better color or fullness. You can buy a spool of tulle with a 40% coupon for Joanns or Michaels (if you have those) and some elastic by the yard.
Look up tutu tutorials. A simple one consists of a band of elastic and tying the strips of tulle in knots at the top. (Buy the tulle on a spool, NOT a bolt.