Essie Instant Dry Oil
I don't think I would have ever tried Essie's Instant Dry Oil if it hadn't been on Fragrance Direct for a ridiculously cheap price. I think it was like £2.50. It isn't in stock any more but if it ever is, then you should definitely buy it!
When I ordered it I thought it would be like Jessica Quick Dry (post coming soon) and it would make my polish dry quicker. It isn't. Instead it's actually an oil and creates a layer that protects the nail from any dents or marks and it does really work. But it doesn't technically make your polish dry any quicker.
The oil doesn't go anywhere after the nail polish is dry, you'll still have a layer on your nail. I either rub off the excess with a tissue or just rub into the nail as it's basically mineral oil and perfume.
A unique product which I'm glad I have in my collection but is not an essential. Especially if you cannot get it at a cheaper price.