1 courgette
a few cloves of garlic
Olive oil
Portion of dried pasta (100g from a 29p pack of penne from Lidl or Aldi)
Salt and pepper to taste.
Grated cheese
Slice courgette and crush garlic cloves lightly (No need to peel)
Cook pasta as per instructions.
Meanwhile, sweat the garlic in a decent layer of olive oil Add the courgette slices and fry gently.
Drain pasta and add to courgettes and garlic, mix.
Remove garlic (or not, if you like)
Season to taste.
Add grated cheese.
Also perfectly good cold if you make more and keep the leftover portion(s) in the fridge. I've never tried freezing it.
Yes, this does involve having things to hand such as olive oil, but you have to haven some staples anyway and even using it as an ingredient, as in this recipe, a bottle of oil will last for ages. The most expensive recipe-specific item is the courgette, but even they aren't that pricey if you shop at a sensible supermarket / greengrocer, or market (if available - and not the 'everything organic at twice the price of Waitrose' variety

).