There is a thread about this from 2013 which I read after Googling this topic but it's still not clear to me whether it's only free if you have unlimited data as in that thread someone said it was free but you had to pay for data which doesn't make sense to me. If you do pay for data then what facility of Snapchat is free?

Snapchat itself is free - it just means the data it uses may be chargeable depending on your mobile plan. For example if you have a plan that includes 1GB of data then snapchat will just use a (typically very small) portion of that data allowance.

Thanks for that. A simple explanation explained simply

as others have said the costs that can be involved are basically data costs if you run out of data here is a print screen of what my snap chats used since the 17th obviously every ones usage is different it depends how many you send and how many you receive, But if you are on a limited data plan then like most users on one you most likely use wifi a lot anyway and snapchat works perfectly fine on wifi so its nothing much to worry about

Ash