Ivana my Dh always takes his own lunch tyo work but he does actually throw it together himself!
Being Asian it has to contain rice, so he has a chunk of rice, then adds stuff like marinated pork spare ribs, or chicken wings, drumsticks, casseroles, stews, noodles, he will cook his own chicken gizzard & eggplant chilli something or other (I wont eat anything containg inners of animals!)
If we have left over lasagne he will have that without rice, sometimes on a Sunday afternoon he'll cook up a big pot of fried noodles with prawns, eggs, veggies etc & add a chicken wing...

He has never bought lunch & it does save money, I too always take my lunch, which is asalad sanga's or bread that I toast at work & then top with avocado & sweet chilli tuna (OMG it's so yummy!) But I also will take in some of what DH has prepared!!!

God Luck, I hope he appreciates it!

The Slow cooker is great, I never use less than 2 kgs of meat at a time & make uup huge curries etc with cheap meats & have it 2 nights in a row & then freeze the rest for a week or so times & Dh has some for lunch it goes a long way!!!!