I've used WD40 on a trumpet and it worked fine, at least for a one
hour practise session. I have no idea how it would do long term.
Valve oil is pretty cheap at any music store.

That's for the valves. Don't forget there are slides, probably four
of them, and they all have to work to play in tune. I use lanolin on
these, probably vaseline works too.

Don't put oil on a chain. Use wax, there is a special wax from the
bike stores that is much better. Airgun shooters put it on their
pellets.