LinkedIn is expensive. CPCs routinely run 5-10x what you'd pay on Meta or Google for the same person. The question isn't whether it's expensive, it's whether the audience quality justifies the premium.
High-ticket B2B where one customer is worth $10K-1M+. A $200 cost per lead and 10% close rate = $2K CAC. On a $50K annual contract, that's 25x ROI over the first year.
Low-ticket B2B (under $5K ACV). A $200 CAC can't pay back on a $2K annual product. Meta or Google Search usually works better at that price point.
Below $3K/month, LinkedIn doesn't get enough data to optimize and you can't iterate. If your budget is under that, skip LinkedIn and run Meta/Google until you have scale.
For some B2B, using Sales Navigator for targeting + cold email or LinkedIn DM outreach (manual or automated) produces similar quality leads at a fraction of the cost. LinkedIn Ads is for when you need scale.