vmI, I must try and solve your problem in 5 minutes to help you find a healthy lunch.

1 cucumber
1 tomato
1 khas leave
1 quarter onion
1 tin of tuna fish
2 slices of bread.
littile pepper and salt.
total cost is 10 riyals

put all of the above ingredients in a grinder or food processor and then make into a sandwich. Place the sandwich in a 'sandwich maker' you know the ones that heat up! Have it with a glass of fresh orange juice.
When you buy bread, buy brown bread from Giant Store it is high in fibre and healthy.

If you try this, you will never again buy a sandwich. Good luck and I hope you are not too lazy to do it!