There is one obvious advantage:

You've seen it coming!
Buy now and get nothing for free!
Well, at least no free beer. Perhaps a bear, if you can afford it.

Now that you've got...

your bear, you have to admit it!
No, we aren't selling bears.

We could talk about renting one.

Rent one bear, ...

get two for three beer.

And now, for something completely different.

Red
  Fancy stuff about red thingies.
Green
  Green! Green! Green!
Blue
  Cool kids are blue.

Tennis
One ball, two players. Lots of fun.
Soccer
One ball, 22 players. Lots of fun.
Baseball
Well, one ball, some guys running around, some guys hitting others with a stick.
Sounds like fun, doesn't it?
Well, apart from the running part.