how much is one giygabyte?

[melissa]

I got a plan with sprint and usually I have unlimited everything but with sprint I have one gigabyte in my plan. how long will that last me and will I be using my gigabytes if I was to use apps like games or instagram, I know the girl at sprint said I probably shouldn't be using Pandora or youtube which confused me even more because now i'm scared to download or use any app. im very confused on this whole giygabyte thing and about downloading and not using apps or internet