Ice is great for boo-boos, but marshmallows are even better because there are no pointy edges. I have a package in the freezer, still in it's original bag, to use for headaches, bruises or other boo-boos. ;)
The small lemon shaped plastic juice containers can be reused for a small ice pack. This is a page about using lemon juice containers as an ice pack.
Rather than buying therapeutic ice packs to use for pain, try making your own. The process is easy and this page contains ideas, including the materials needed for putting together homemade ice packs using alcohol.
This is a page about making an ice pack with rice. This easy to make ice pack comes in handy for bumps and other injuries.