Recommend a regular lubricant / oil

[Dizeee]

I have been neglecting my chain and cassette again and its a bit grindy so I have just washed the bike down and want to get some sort of cheap spray that I can just spray on once a week or so after a wash to keep things in check.

I have WD40 and have been advised to use it, however I know some say do not use that as it stretches the chain / has a negative affect on the mechanics.

Any recommendations for a lube or spray I can just chuck on fairly frequently and forget about?