My Samsung Galaxy Ace default message is multimedia type messages (70 characters) and is costing me a fortune, over 10p a text (UK). How do I change this to normal text (160 characters) which my phone company gives me 200 free text making it cheaper for me?
AFAIK the stock Messages app always sends a SMS unless you've added an attachment (picture, video, audio), or if you are typing a very long message (the latter depending on your settings). If there is an attachment the message will show the number of used KB instead of the number of remaining characters.
That being said, you should check if the message centre number in your SMS settings is correct. To check start the Messages app, click
Also on the same screen there is a setting that may convert long text messages automatically to MMS, so you might want to turn that off.