All free! Free for life!

ChatWork Install Link:
https://chrome.google.com/webstore/detail/chatwork-chatgpt-gpt4-fre/mlinajkbaceacmgohnehoopkmajnleaf

Gptchat™ is a chat app, chat with AI. It integrates powerful AI, including:
GPT-4 8K AI model (openai GPT4)
chat gpt-3.5-turbo AI model (openai ChatGPT)
chatgpt-prompt-generator-v12 AI model (for optimize prompt)
finetuned-gpt-neox-20b chatbot AI, which is a GPT-3-like AI.
finetuned-gpt-neox-20b product copywriting AI.
finetuned-gpt-neox-20b question answer AI.
a database that contains 1000+ GPT prompts.

One more thing, the same account can also use Chrome extension & Web &  Pro versions available! You can click ? icon to discover it. 
So, try it!

New Update:
This add-on has integrated the latest version of chatgpt model (openai chatgpt)

ChatWithGPT, powered by chatgpt AI model.
ChatGPT_QA, powered by chatgpt AI model,
DiscussWithGPT, powered by finetuned-gpt-neox-20b chatbot AI model.
QA_5W2H, powered by finetuned-gpt-neox-20b question answer AI model.

In future, we will also integrate other powerful AI and AI functions, so stay tuned!
ChatGPT Model Info:
ChatGPT is powered by gpt-3.5-turbo, OpenAI’s most advanced language model.
you can build your own applications with gpt-3.5-turbo to do things like:
Draft an email or other piece of writing
Write Python code
Answer questions about a set of documents
Create conversational agents
Give your software a natural language interface
Tutor in a range of subjects
Translate languages
Simulate characters for video games and much more

GPT-NeoX-20B AI model Info
GPT-NeoX-20B is a 20 billion parameter autoregressive language model trained on the Pile using the GPT-NeoX library. Its architecture intentionally resembles that of GPT-3, and is almost identical to that of GPT-J-6B. Its training dataset contains a multitude of English-language texts, reflecting the general-purpose nature of this model. See the accompanying paper for details about model architecture (including how it differs from GPT-3), training procedure, and additional evaluations.

Model details
Developed by: EleutherAI
Model type: Transformer-based Language Model
Language: English
Learn more: GPT-NeoX-20B: An Open-Source Autoregressive Language Model. For details about the training dataset, see the Pile paper, and its data sheet.
License: Apache 2.0
Contact: to ask questions about this model, join the EleutherAI Discord, and post them in #release-discussion. Please read the existing GPT-NeoX-20B documentation before asking about the model on Discord. For general correspondence: contact@eleuther.ai .