Where can I buy Rune Arc?

Excuse me, I'm a bit confused. Could you please clarify where exactly I can purchase Rune Arc? I've been looking around but haven't found a reliable source yet. Is it available on a specific online exchange? Or perhaps there's a physical location where I can buy it? Could you also recommend any trusted sellers or platforms that I should consider? I'd really appreciate your help in this matter. Thank you in advance for your assistance.