Model your product pricing, product cost (COGS), and target customer acquisition cost (CAC) to calculate break-even ROAS and monthly net profit before scaling paid ad spend.
ROAS = Total Ad Revenue / Total Ad Spend
Break-Even ROAS = 1 / Gross Margin %
At 50% gross margin, your break-even ROAS is 2.0x. At 60% gross margin, break-even is 1.67x. At 70% gross margin, break-even is 1.43x.