If you go to a place such as Autozone or OreillyAuto they will usually take your old battery out and change the battery for you using the new battery you buy from them.
The new replacement car battery costs between $50.00 to $100.00 depending on the battery brand and how big of a battery your vehicle needs.
If you have an auto shop install the battery for you then they might charge you $10.00 to replace the battery.
Replacing a battery is pretty easy to do and you just unhook the negative and positive battery terminals and then reconnect them to the correct post.
The - is the negative or black battery cable and the + is the red or positive battery terminal.
If someone brings me a battery from another place then I will install the new car battery for $10.00 which is a pretty good deal.