The birth control sponge is a product that is soaked with spermicide. That sponge is placed into your vagina before you have sex and must stay in your vagina for a few hours after sex before you remove it. It's probably one of my least favorite forms of birth control because it is not as effective as other options.
In general, condoms are the best form of birth control that you can buy at the pharmacy without a prescription. If you are considering other options, unfortunately they are not nearly as effective, and you're setting yourself up for failure.
Again, condoms are the most effective form of birth control that you can buy without a prescription. If you don't have a prescription for the options that you want, you can always go to your doctor or your nurse practitioner and discuss your options in detail so that you can pick the best form of birth control for you. Until then, use condoms.