Di, a mate of mine does that. Buys his favourite farmhouse loaves from Sainsbury's and has them cut med thick. When home he puts two slices in zip-lock bags and freezes them in batches.
When he needs a sarnie for work or lunch its easy-peasy to defrost them.
Saundra, if you buy a loaf mix make sure you use it before the use by date as yeast will 'go off' and not perform the job it is supposed to do.