Quote Originally Posted by iCake View Post
We say спасибо за + accusative. The rest of your Russian is good
Some more rules of thumb for you. (In this case "for you" is "для вас", since you are supposed to USE those rules, you NEED them, and you somewhat BENEFIT from them).

If you say "спасибо для ваших ответов" it sounds non-Russian of course, but I would like to underline what it means: it means as if your "спасибо" is needed for "our answers", as if "our answers" will use your "спасибо" in some way. That is why it sounds strange.
You can say "тетрадь для записей" (a writing-book for (making) notes), because this "тетрадь" is intended to be USED for making notes in it. One needs "тетрадь" to make notes. So, "тетрадь для записей" is OK.
You can say "книга для детей" (a book for children), since this book is intended to be used by children.
You can say "стоянка для машин" (a parking for cars), since the cars are supposed to use this parking. This parking is needed for cars. Although, you can also say just "стоянка машин" (a parking of cars), which is correct too.
You can say "ручка для письма" (a pen for writing), because this pen is required for writing, it is used to write.
You can say "тарелка для супа" (a plate for soup), since this plate is going to be used to pour some soup in it, it is needed for soup. Do not confuse it with "тарелка супа" (a plate of soup). In this case, they are different: "тарелка супа" is a plate with soup in it. "Тарелка для супа" can be an empty plate.

Now if you compare "тетрадь для записей", "книга для детей", "стоянка для машин", "ручка для письма", "тарелка для супа" etc. you will see something in common in all of them.
And compare it with "спасибо для ответов". Do you feel it does not match the pattern above?

The preposition "за" has a different meaning. One of its meanings is "in exchange of something". You give "спасибо" in exchange of our answers. So, the right way to say it is "спасибо за ваши ответы!"

If you pay for something, you give money in exchange of what you buy: "заплатить за обучение" - to pay for education.
"Он платит мне 10 долларов в день за мою работу" - He pays me 10 dollars a day for my work.
"Я хочу вас поблагодарить за вашу помощь" - I want to thank you for your help.

You can also use "за" in noun+noun combinations:
"деньги за работу" is "money for work" (money which is paid in exchange of work)
"5 рублей за билет" is "5 roubles for a ticket"
"благодарность за услугу" is "gratitude for service"

And one more example to underline the difference between "для" and "за":
"деньги за работу" is a typical expression which means "money (paid) for work", i.e. it is money in exchange of someone's work.
"деньги для работы" is a bit strange, but theoretically possible. This one means "money you need for your work to be done". Imagine, your work involves bribing some powerful people This is actually you job: you are a secret agent, and you bribe some officials, so you force them to make some "correct" decisions. Jokingly In this case, the money you need to do your secret job can be called "деньги для работы".