The amount you spend isn't the amount that leaves your account.

Brokerage is the fee your broker charges for executing your order. Many apps advertise ₹0 or flat-fee brokerage on certain trade types - but brokerage is rarely the only charge on a trade.

A single trade can involve several small charges beyond brokerage, including:

• STT (Securities Transaction Tax) - a government tax on the trade itself.
• Exchange transaction charges - a small fee the exchange takes.
• GST - charged on brokerage and some other fees.
• SEBI turnover fee, stamp duty, and DP charges (when you sell, for moving shares out of your Demat account).

On a single trade, these charges are usually small. But if you trade frequently, they compound - and more importantly, they mean your break-even point isn't the price you paid. A share needs to rise by slightly more than 0% just to cover what you paid in charges before you're actually in profit.

This isn't a reason to avoid investing - it's a reason to read your contract note, not just the headline “zero brokerage” claim.