Phase 1 · Building with LLMs · Prompting
Choosing a model
Trade capability, speed and cost across model families.
Open this lesson Create a free account
Why it matters
The same feature can cost $20 a month or $2,000 depending on the model behind it, and the cheapest model that does the job well is rarely the one people start with. Knowing how to compare models, and how to do the cost math before you ship, is one of the most practical skills in AI engineering, and one of the easiest places for a marketer's instinct for budgets to shine.
What you'll be able to do
- Compare models on capability, speed, cost, context window and features
- Estimate what a feature will cost per request and per month
- Pick a starting model for a task, and know how to test a cheaper one
- Explain the difference between closed API models and open-weight models
Before this lesson
Next in this phase: Reasoning models and effort