Hi!
What’s the best way to go to Wings of Tatev from Yerevan in one day?
With a driver or a tour.
You mean those minibus tours that stand in the center? With all kinds of tours to different places?
Depends on what exactly you want to get from it. You can go with them — it’ll be cheap, quality depends on luck. You can go with companies that have good reviews, also not expensive, but then it’s a group and a fixed program. You can go individually (a normal guide wouldn’t take you there in one day, but surely someone will). Or you can just hire a driver — that’s comfortable, fast, and you only go where you want.
As for prices:
street tours — 10,000–20,000 dram per person,
through companies — 15,000–30,000 dram per person,
individual tours — 60,000–120,000 dram per car,
with drivers — 50,000–80,000 dram depending on the car.
By companies, do you mean services like Sputnik8 or GoTrip?
Those are carriers, not tour companies. Search for group tours on Google, there will be many actual tour companies there.
Also check out Hyur Service Tour. I started getting to know Armenia with them. You can book different excursions on their website and pay by card. Tours start from the center, their office is on Nalbandyan Street.