I was debating on getting an iPhone 4s?

I want an iPhone 5 but they cost to much so I was thinking of getting an iPhone 4s. The reason I say it costs to much is because I'm on Virgin Mobile so I have to pay full price when I get a new phone. My question is, I have a LG Optimus Slider phone right now. If I did get a iPhone 4s would I see any type of speed increase on the internet? Or would it be the same? I know it looks like its still 3G which is why I was asking. My main thing about getting a new phone is I want faster internet speeds. So would getting an iPhone 4s be faster or should I just get a cheaper 4G compatible phone?

Its a good phone.