For the potato dish, you need one onion, eneugh potatoes for four people (5 large ones should do), peel and cut both the potatoes and the onions very thinly then boil the sliced potatoes for about three minutes, on a tray put a little olive oil and smeer the bottom of it to cover it, then cover the bottom with a layer of potatoes then you leithal some chopped tomatoes to cover the potatoes, then spread some onions to cover the tomato, then sprinkle some salt black pepper and some slithers of garlic, repeat the process, and finally cover it with a third layer of potatoes, cover all of that with some foil and place it in the oven for 40 minutes, after that take it out remove foil cover it with greated cheese and sprinkle some oregano, dried or fresh either will do. Back in the oven for 15 minutes more (gas 200c all the time).
Ten minutes away from them being cooked you should heat very well a grill pan and drizzle a little oil and start cooking the skewers, browning and turning around and so on until all sealed in then cook until fully done.
Serve it on a plate and you're done...so easy you don't even need a recipe and again under a £5.00. Don't say I never helped you. :)