Moving out with a friend soon, need advice...

okay so in the coming months me and my friend are moving out into a two bedroom apartment or house and renting it.

we have sorted our budget for the big stuff; Rent, Council tax, Bills.

Now we are on to planning how to budget our expendable income and we are including food in this.
How would you guys recommend spending on food, are there any apps we can use that will help us locate the best place to go for product X or an offer available on product Y. we are looking to improve our overall diet as well, i am looking to improve my physical fitness in terms of muscle and he is looking to become generally healthier so any tips on how to incorporate that into our budget would be great and warmly welcomed advice (and yes i know about rice and chicken we just get bored of it very quickly even though we are seasoning and spicing it).

we have estimated a total of £200 on food between (or £100 each if you cant be bothered doing the maths ;)) would be sufficient per month to spend on food leaving us with a decent amount of cash left over for personal expenditure.