Cheapest vs priciest AI video on Sume: a per-second spread of 114x

On Sume, the most expensive per-second video size is Seedance 2.5 at 1080p, about $1.42155 per second, and the cheapest is Grok Imagine Video 1.5 at $0.0125 per second, a ratio of about 114 to 1. The two are not substitutes: Grok Imagine Video 1.5 only takes a still image and animates it, while Seedance 2.5 makes a clip from text, images, video or audio references (Sume video docs, read 2026-10-06).

A more useful spread compares text-capable models at the same resolution. At 720p, Seedance 2.5 costs $0.5778 per second and Wan 3.0 costs $0.125, a ratio of about 4.6 to 1.

What are the ratios against the cheapest text-to-video size?

Here the base is Gemini Omni Flash 1.1 at 360p, $0.0375 per second, which is the cheapest size that accepts text prompts in this table.

What does the spread mean for a budget?

Two decisions drive almost all of it: model and resolution. For Seedance 2.5, moving from 720p to 1080p multiplies the price by about 2.46, because the token count rises with pixels and the 1080p list rate per 1,000 tokens is higher ($0.0234 against $0.0214). For Wan 3.0 the same step doubles it. Aspect ratio barely moves the price: across 16:9, 9:16, 1:1, 4:3 and 21:9 the Seedance 2.5 figure stays within about 1 percent.

If you do not need the top price, start every new concept at the cheapest size that shows the idea, then spend on the final. A 5 second Seedance 2.5 clip at 720p is $2.889; the same prompt as a Wan 3.0 720p draft is $0.625.