Thinner at Sally's is only $4.29 unless you have a card, then it is $3.79 for an 8 ounce bottle! I even use this in my Seche Vite top coat and my Nail Tek base coat. Saving one bottle of those is worth way more than 4 bucks. To temporarily thin you can also run running hot water from the tap over the bottle of polish. It can get you through one mani. Never use Polish Remover. The thinner replaces the ingredients in the polish that made it the right thickness, before it evaporated. Always cap your polish tightly. Remover removes, thinner thins.