There is no per-unit API price: self-host only.
There is no free API. The weights are open, so you can run it yourself.
#26 of 27 in Multimodal.
On MAEB v1 audio-only · Audio Pair Classification · English, Speecht5 Multimodal scores 57.9 vs 58.9 — about the same.
Released 2022-05-16. It is the current version in its line.
Yes, the weights are open (MIT licence).
The weights are open and can be self-hosted; hardware needs are not confirmed yet.
Speecht5 Multimodal is an open-weights embeddings & retrieval model from Microsoft, released May 2022.
EmbeddingGemma 2 (better).