"Furniture" is used as a collective noun so use the singular. Remember to capitalise company names. It's "Ikea".
I bought a lot of furniture. It's all ready to be assembled.
I bought some furniture and now I have to put it all together.
In your second sentence, the comma between "Amazon" and "com" should be a full stop.
In your third sentence, you used "thread" instead of "threat".
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