The main thing with bike lubes is you don't want stuff that's going to attract grit. As far as lubes your family might have lying around the house, gun oil or sewing machine oil are lightweight enough to serve. WD-40 is (as its name suggests) a water displacing penetrant, not so much a lubricant. It attracts tons of grit. I don't recommend it on bikes, except on a rag used (with nitrile gloves!) to take road tar off your frame before washing. It's a good thing to use on tools at the end of a season or when they'll be stored for a few months without being used...
There are as many opinions about lubricants as there are riders and riding conditions. My personal choice is Pedro's soybean-based Go! (lightweight for dry conditions) or Chainj (heavier for muddy or rainy conditions).
Whatever you use, make sure to wipe off any excess THOROUGHLY. The parts you're lubricating are between the plates and pins of the chain, inside the moving parts of the derailleurs and brakes. Any bit of oil left on the outside surfaces will just attract grit, that will work its way inside and cause wear.
Speed comes from what you put behind you. - Judi Ketteler