While driving the battery light turned on, now it will not start?

Yesterday I turned on my car and drove for about 30 seconds until the battery light came on, so I decided to turn around and drive home. Then the VSA light came on too and the brake light. After I got home, I decided to turn it off and when I tried turning it back on the car was completely dead. A few hours later a neighbor helped me to jump start it and the car would not start at all, only some lights turned on, but it wouldn’t start even after 10 15 minutes. I don’t know if I should buy a new battery or if it’s the alternator, but my car was driving fine before it didn’t make any weird noises or anything out of the ordinary.