I have found the below vendor on Aliexpress to be quite good. I have ordered 3 boards from them on three separate occasions. All were shipped within 24 hours and arrived in the US in 9 - 10 calendar days via Aliexpress Premium shipping ($4.11 shipping). I have had other vendors take 3 - 5 days to ship, not ship at all, message me about raising the price, etc.
Aliexpress link weirdness. The price shown below is for the antenna even though the picture is the board. The board is currently $120USD.