Last week I used this tip, and got me some new nail polish on ebay. I ordered Risky Business from Essie here (around 40 dkk) and Dry fast top coat from Seche Vite here (around 40 dkk). I ordered them together, so I saved a bit on delivery cost.
Both are brilliant, although I still prefer Chanel Le Vernis to any alternative. But the top coat is the best I've tried so far. But the seller also offers products from O.P.I. on very reasonable prices.