Turkey is the cheapest shard we sell, and by a clear margin. If you are optimising purely for Blue Essence per dollar, nothing on this site beats a TR account — the same 90,000 essence that costs $35.99 on NA lands well under thirty here. For anyone building a large champion pool to practise with rather than a ladder account to care about, this is the answer.
The trade-off is the obvious one: unless you are in the region, ping will be the limiting factor, and the ladder runs on its own culture and its own meta. Plenty of buyers take a TR account purely as a sandbox — somewhere to own every champion and try things — and keep their competitive play on a shard closer to home. That is a perfectly good use of twelve dollars.