Superdrug sell a very cheap hair oil called Got2be. It's usually on offer. I use this before bed if I'm washing hair in the morning (can't venture out of house without washing it off, believe me!)
The next one always found in my hair is a sadly discontinued product from Redken called All Soft Velvet Whip. This is witchcraft in a bottle, I tell you. My overprocessed hair adores it and it doesn't weigh it down!
I have a "saved search" on Amazon and eBay for this (and a little stockpile at home)
The next one that was a lifesaver for my hair was by John Frieda. He made an amazing range back in the late 90's called "Beach Blonde" and I had everything from the range, it was that good! The one thing left from those days is 'Shine In The Spotlight Glosser' (which is basically silicone in a tube), I achieve shiny hair but greasy and weighed down very quickly. Trick with this is to apply to properly wet hair, not damp and to blow dry straight away. Or to apply to wet hair, don't brush through, don't touch at all and I get very nice, defined waves.
As I'm a habitual hair-fiddler this is difficult....