You can express a directional bet two ways: buy a single option, or trade a spread (buy one strike, sell another). Both are legitimate; they just fit different jobs, and scalping has strong opinions.

The single long option

Buying one call or put gives you maximum gamma and responsiveness, a dead-simple position, clean fast fills on liquid strikes, and a max loss capped at the premium. The cost: you pay full premium and eat full theta. For a quick in-and-out on a level-to-level move, that's a fine trade — you're not holding long enough for decay to dominate.

The spread

A spread sells a further strike to finance part of the trade — cheaper entry, less theta bleed, defined risk. But it caps your upside, adds a short leg with assignment risk, and is harder to fill quickly on thin 0DTE strikes because the whole combo has to price. Speed is exactly what a scalp needs, and the spread trades some of it away.

Spreads win on cost and defined risk; singles win on speed and simplicity. Fast scalps live and die on speed.

Which to use

For a fast, near-the-money 0DTE scalp, the single option usually wins — clean fills, full responsiveness, one thing to manage. Reach for a debit spread when you want a slower, defined-risk bet toward a specific level and are willing to trade speed and upside for cheaper decay. Match the tool to the trade, and default to simple when the clock is the enemy.