In the near future I see a lot of miners being turned off after the big dump of the halving. We'll climb price based on speculation and then when the magical moment hits we'll see huge sell off.

Don't expect to earn money (not even ROI) with inefficient (outdated) hardware, and especially in places where the electricity is that expensive. I had access to 0.08 USD per 1KW and even with that price it would not be profitable to mine with that device. Mining as a hobby is not possible anymore unless you want to slowly lose money over time.

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Mod hint: Please refrain from posting several posts in a row and try to group posts whenever possible.

If OP is just wanting to learn he could use a Compac usb stick miner. It's still the most recent stick miner.  For just learning it is great as it makes the person learn some of the command's.   So I consider it educational. 

Now if OP is looking for best bang for the buck then full machines are going to be what he want's.  But we really need to know electricity price as you pointed out some are old and could be like losing money every day it runs.  Which is not a ton of fun.

If you buy a old miner, calculate your ROI before investing.
https://bitcoinwisdom.com/bitcoin/calculator

Old miner are not efficient.

how about an age of bitcoin? seems interesting didn't it?

Look for a Bitmain S1 or S3,bout as cheap & easy as it gets