Covergirl range: Outlast Stay Brilliant Nailpolish (11mL).
The guy I called couldn't confirm whether this product and price would be in other stores state or nationwide, but for Coles Tooronga, the deal ends on the 21st September.
I haven't tried Covergirl nailpolish, but a quick google search came up with favourable reviews.
There were plenty of different colours (over 15+ I'd hazard) and all of the colours I bought (I purchased 7) are sold at Priceline for $6.95.
It's a very good price for a decent size and the quality seems quite good too (not too thick, nice sized brush, seems to dry quite quickly as well).
Ulta3 is known as a "cheaper" brand as reflected in its normal price of $2-3, but is still pretty decent quality.
***Note: Particularly with the Ulta3 glitter polishes, open them and check the consistency of the polish, as I found that most of them were thick and gluggy, therefore unusable. However I had no problems with the Covergirl polishes.
Also, the Covergirl polishes weren't recognised in self checkout, so I had to call an assistant over.