1. For asking the price of something:
* Сколько это стоит? (Skol'ko eto stoit?) - This is the most common way to ask the price of something.
2. For asking the quantity or amount of something:
* Сколько этого? (Skol'ko etogo?) - This is used to ask how much of something there is. For example, "How much milk is there?"
Here are some examples:
* Сколько стоит эта книга? (Skol'ko stoit eta kniga?) - How much is this book?
* Сколько стоит билет на поезд? (Skol'ko stoit bilet na poezd?) - How much is a train ticket?
* Сколько у вас апельсинов? (Skol'ko u vas apelsinov?) - How many oranges do you have?
* Сколько времени вам понадобится? (Skol'ko vremeni vam po-nadobitsya?) - How much time will you need?