Condoms and spermicide will prevent pregnancy if used before sex.
If you are already pregnant, there is nothing in a store to terminate it in the US.
If you have had unprotected sex within the past five days, you can get emergency contraception over the counter in the store to reduce the risk of pregnancy. The most reliable methods of emergency contraception are available from a health care provider, though. The most effective is the copper IUD.
If you are already pregnant, I would still advise going to a Planned Parenthood and discussing your options. You can have an abortion up until around 3-4 months of pregnancy or later, depending on your states laws.
If you dont want to have an abortion, you can discuss whether you want to keep your child or put it up for adoption.
You may wish to consider adoption. There are many variations possible. Some states, such as California, have a no-questions-asked baby drop-off at hospitals and fire stations---other states may do as well. But if you prefer to have some input into the adoption process, even choosing the parents for the child, then you can have anything from an open adoption (where you keep in touch with the child all through their life), semi-open (some exchange of letters and photos through a third pary), or closed (no contact). There is a lot of freedom of choice. A specialized adoption lawyer can set you up. Generally, there is no or very low lawyers fees for the woman putting the baby up for adoption---the adoptive parents foot the bill. The local Childrens Aid Society can put you in touch with a social worker specializing in adoptions. There are lots of choices and options available.