Recent research by I Can't Believe It's Not Butter found that nearly half of British workers now regularly eat at their desks, with one third choosing to do so because of the financial savings.
According to food and nutrition writer Amanda Grant, homemade sandwiches represent a simple way to save money.
Speaking on behalf of I Can't Believe It's Not Butter, she said: "To buy a sandwich out can be expensive, but to buy a loaf of bread and to use store cupboard ingredients - like tinned tuna, tinned sardines - and also using leftover meat - roast chicken, ham, pork - and use the sorts of things you generally have at home is much cheaper than buying sandwiches that are ready made for you."
Ms Grant suggests using quality bread - preferably wholemeal or granary - with a healthy filling, along with a large glass of water for a nutritious and affordable lunch.
However, she emphasised: "Do some of the things you might like to do if you were at home by trying to switch off from work so that you do feel like you've actually had time away from working."