You can find better prices than Nexa by buying from CN.
But cheaper is rarely better.
IME, Nexa has the best customer service and speed, and great testing. There’s a dedicated TG where his products are third-party tested (vials are randomly selected and sent directly to the lab), this is on top of his own testing.
I started with domestic single vial sellers, which are quite expensive. But their service was fantastic. I don’t have the patience nor the tolerance for dealing with CN nonsense, crypto, slow deliveries, customs, none of that. So I’m willing to spend a wee bit more.