Avatar had a high budget of $200 million, extensive advertising, and was directed by a well-known director, characteristics of a mainstream film. In contrast, The Blair Witch Project had an extremely low budget of only $60,000, minimal equipment like handheld camcorders, and unknown actors improvising lines, marking it as an independent film. Niche films like Piranha have a specific target audience, higher budgets than independent films but lower than mainstream, and focus on unique concepts that have endured over time.