I am using a Lumia 520. I want to send a message to my friend and that message should include the $ symbol, but I can't find it. Can someone please help me with that?
You're probably using a keyboard other than US English. To get the $ sign, switch to symbols by tapping on the &123 button in the lower left corner, then tap and hold on the button corresponding to your local currency to get a list of alternative currency symbols. The $ sign should be listed there.
For instance, with the UK English layout, I need to tap and hold on the £ button: