To create a real cheap and simple but efficient swing:

- just get a pool foam noodle (with a hollow core) at Wal-Mart, K-Mart or some super market,

- a piece of 3/4" poly rope from Home Depot or so

- a place to tie the rope to

- string the rope through the noodle,

- attach the rope ends,

- sit on the noodle and

- swing!