You cannot buy Overwatch Credits (white currency) with cash. They are strictly an earned "freemium" currency.
Earned via Battle Pass (Free and Premium) and hero progression.
Understanding Overwatch Coins and Credits for Skin Unlocking overwatch buy credits
Shop bundles, new Legendary skins, and the Premium Battle Pass.
Reports from community platforms like Reddit and the Blizzard Forums highlight several recurring issues: You cannot buy Overwatch Credits (white currency) with cash
Players who owned Overwatch 1 had their existing currency converted into these Credits, often referred to as "Legacy Credits". Critical Shopping Reports & User Issues
To "buy" Credits, you must purchase the Premium Battle Pass using 1,000 Coins (~$9.99). This unlocks a track where you can earn up to 2,000 Credits (1,500 free + 500 premium) per season. Understanding Overwatch Coins and Credits for Skin Unlocking
Legacy (OW1) cosmetics and select OW2 items in the Hero Gallery. Yes , via the in-game shop or Battle.net . No , they cannot be bought directly. Analysis of "Buying" Credits