South Korean virtual asset exchanges are competing for users with zero-fee Korean won trading promotions, but thin order books can make slippage more expensive than the commission saved. Coinone and DigitalX, formerly Korbit, launched the campaigns on the 26th and 24th of the previous month, respectively. A 20 million won trade would incur a 10,000 won fee at a 0.05% rate, but execution 0.1% above the market price would add 20,000 won in slippage. CoreSecurity found DigitalX's average daily volume rose more than ninefold to 10.085 billion won after its promotion, while Coinone's increased nearly 40% to 5.536 billion won. However, RLUSD accounted for about 647.43 billion won of DigitalX's three-day cumulative volume; excluding that stablecoin, growth was 19.1%, and excluding all stablecoins, volume fell 16.6%. Investors are advised to assess total trading costs, including order-book depth and execution prices, especially when placing large market orders for illiquid altcoins.