Whatever is stored in the blockchain is immutable which means I can fetch this data back in the future. As of today (2016-feb),

• How does one store a 1kb, 10kb, or 100kb or arbitary data/text in the ethereum blockchain? What is the code needed to do this?

• Once stored how do you download the data back onto your desktop?

• How much would this cost exactly in ether/gas/fiat at todays prices?