I love Hourglass Dim Light, but tried the ELF Illuminating Palette as I like trying known dupes and its identical, but a fraction of the price. Wouldn't go back to Hourglass now.
Also ELF Bronzing Palette in Golden (I swirl a brush over all the colours to mix them), doesn't look muddy but gives a fantastic sort of lit from within glowy tan, I've repurchased many times now.
Blue tinted eye drops, really make your eyes sparkle and makes a huge difference to my face. I only use occasionally though.
Physicians Formula CC cream, a dupe of IT Cosmetics CC cream, looks and feels identical on but doesn't have silicone (which the IT one does) and silicones cause breakouts on me. Plus its much cheaper.
Becca Backlight Priming Filter, its the only expensive product I'll continue to repurchase and its my Holy Grail. No matter how tired, flu ridden or run down I look it erases all that and gives me film star skin every time. The transformation is genuinely shocking, and it doesn't dry my skin out. It also looks amazing without makeup over the top.
Nyx blushes in Electro and Red. I used to go for subtler coloured blusher, but tried these on a whim and a very sparing amount of vivid blusher looks so much better on me, more natural too.
Lastly, putting Vaseline all over my face before bed as the last step in my skincare routine. I will never go back to not doing this as it makes such a huge difference to my skin. Doesn't clog pores and sort of locks in your skincare and helps it work more effectively. I wake up with glowy plump skin every morning, no small feat as I have insomnia.