I don't know if this is a popular way of catching ballons because I found out about it by accident, but if you have no slingshot, you can still follow the balloon to the cliff and then, when the balloon is nearly on eye-level with yourself, hit it with your shovel. The balloon will explode and you can pick up the present as if you've shot it with the slingshot.
Maybe this is hopeful for some people who do not have the slingshot yet.
Maybe this is hopeful for some people who do not have the slingshot yet.