In reality this is no big problem for us. You have always a context and can see the real meaning.

Agree with this:

Here elma should be close to the V. Remember we had a discussion about it. Here "elma almak" is like a unit and should be broken. But with accusative:

Ucuz olduğu için elmayı aldım (I prefered the apple because it was cheap)

Elmayı ucuz olduğu için aldım (I prefered the apple because it was cheap)

The underlined parts are emphasized.

The first one is like I was going to buy something else, but I bought the apple instead, because it was cheap.

The second is like a response to the q: Why did you buy the apple? Or, like saying I wasn´t going to buy an apple or anything, but then I did because it was cheap. 

 

 

 

 

Disagree..both have exactly the same meaning.

If you want to say " I was going to buy something else, but I bought the apple instead, because it was cheap." you say, "Daha ucuz olduğu için elma aldım" (I bought the apple because it was cheaper)

If you want to say,  "I wasn´t going to buy an apple or anything, but then I did because it was cheap", you say, "ucuz görünce elma aldım" (seeing it was cheap I bought the apple)

 

 

 

 

If we want to emphasis something we change the order and move it closer to the verb and with proper stress we say what we mean.

 

Ucuz olduğu için elmayı aldım (I prefered the apple because it was cheap)

I prefered apple (instead of something else) because it was cheap.

Elmayı ucuz olduğu için aldım (I prefered the apple because it was cheap)

I prefered apple (mainly) because it was cheap.

 

 

 

 

Sorry sir, there is some wrong information in your post.

We can´t move, for example, "undefined object" to anywere we want in the sentence.OK earllier, I said the same thing For example, "elma" is undefined object and should be placed immidiately before the verb: "ucuz olduğu için elma aldım". You can´t say "elma ucuz olduğu için aldım". Can you? No, I said it before. I had said it the following way:

Here elma should be close to the V. Remember we had a discussion about it. Here "elma almak" is like a unit and should (NOT) be broken. But with accusative:

Ucuz olduğu için elmayı aldım (I prefered the apple because it was cheap)

Elmayı ucuz olduğu için aldım (I prefered the apple because it was cheap)

The underlined parts are emphasized.

I am sure you can also say " ucuz olduğu elma için aldım". 

I can hear your objection on the last one " ucuz olduğu için" is the complement and the object can´t be placed in it. See, you have already begun to learn.

So saying, "If we want to emphasis something we change the order and move it closer to the verb and with proper stress we say what we mean." is a rubbish assumption. Isn´t it? If you say so

Here is additional and useful information for the learners: In Turkish (except da, mı, bile) there can be no word between undefined object and verb. 

We can change the place of the "defined object" as it is clear what it is.

Carefully study the examples below:

 

Yes so what? They are the examples of what I am talking about:

Sinan okuldan kitabı aldı (Q=what did Sinan take from the school?)

Sinan okuldan kitabı aldı = Sinan took the book (not anything else) from school.

Okuldan kitabı Sinan aldı (Q= who did take the book from the school?)

Okuldan kitabı Sinan aldı = It was Sinan (not anybody else) who took the book from school.

Sinan kitabı okuldan aldı (Q= Where did Sinan take the book from?)

Sinan kitabı okuldan aldı = Sinan took the from school. (Not from somewhere else)

The bold parts kitabı, Sinan,Okuldan are also the short answers for the questions. 

A-what did Sinan take from the school?

B-Kitabı

A-Where did Sinan take the book from?

B- Okuldan

A-who did take the book from the school?

B-Sinan

Now let´s go back to your examples.

Ucuz olduğu için elmayı aldım = I bought the apple (not something else) because it was cheap. (Here the apple is emphasized)

Elmayı ucuz olduğu için aldım = I bought the apple because it was cheap (Not for another reason). (Here the reason is emphasized)

What are the possible questions for them?

Q= ucuz olduğu için neyi aldın? => elmayı

Q= elmayı niçin aldın? => ucuz olduğu için

These questions only makes you know what is the object and what is the complement. 

Yours is something like asking "is egg from chicken or chicken from egg" 

Come on. I´m sure you know this emphasizing stuff.

Don´t forget that "ucuz olduğu için" is "belirteç tümleci"  which expresses  "reason" and changing its place doesn´t change its function. Wherever in the sentence you place it, it is the "reason" for the "subject" to "buy apple".

 

Hope it helps Yes it probably would, if they read it.