What are some cheaper alternatives to Grammarly that are equally as good?

+1 – Works pretty well for me when writing in non-native languages, although I don't write anything particularly critical.

This looked very interesting. I tried to find out what data they collect and while initially it looked like it wasn't too much, turns out they capture either URL or domain which is very off-putting to me:

...
To improve the quality and availability of our system, we also store the following information:
...
The page from which the request was sent (e.g. languagetool.org),

Yup, my favorite to use as well. As an added bonus it is possible to self host the server for extra privacy. Though, I never personally tries that.

Be aware that this will create sentence structures that are often very easy to recognize as AI-generated. Specifically, GPT generated as different models have a different way of writing (probably something to do with their training data).

The recognizability of the AI-generated text depends on what you ask it to do with your input. But, if you request a complete rewording, the resulting structure will likely be recognizable as AI-generated by many people.

You can avoid some of that by adding custom instructions.

Avoid starting paragraphs with conjunctive adverbs and phrases. 
Avoid starting paragraphs with the following : however, furthermore, moreover, in summary, in conclusion, the, this.

This is the bare minimum you should add when asking it to completely reword input.

You can probably get much more constructive and detailed feedback if you create more detailed instructions.

Edit: Just because I had some time on my hands and because I thought it was a fun challenge, I did work on a more complex prompt, which I included below. Some notes though:

• The prompt is for GPT4, I am not sure how GPT3.5 does with it.
• There is no perfect result, if you take the complete rewrites you get out of this and put them back into a new session it will find new issues with it as far as sentence structures go.
• I did add rewrites to the output. You still need to review these to make sure they actually fit you as a person. Even with the stuff I added to make it less obviously AI generated it still goes for certain patterns.
• This prompt is a bit overkill, as I just wanted to play around and include all the options I could think about. I'd probably settle on just one or two rewrites, but I wanted to see which one would resemble my own writing style better. An alternative would be to only focus on words being used incorrectly and grammar errors.
• I did spend a bit of time on the prompt, but not enough to perfectly tune it.
• Notice that I did specifically tailor this prompt to online conversations. For a different context, make the appropriate adjustments.

# Role  

Your role is to be a writing assistant or coach.
You do this in the context of online conversations.

# Goal

Your goal is to identify: 
- Sentences that are too long and can be broken up. 
- Sentences that might be unclear. 
- Sentences that might be shallow and not expand on the point being made. 
- Repetitive writing. Sentences that repeat earlier made points for example.
- Words used potentially incorrectly because of their meaning. 
- Grammatical errors, typos, and punctuation mistakes that need correction.

# Parameters  

- If a line starts with "Instruction:" It contains extra instructions.
- Do not alter or analyze lines starting with >. These are markdown quotes.
- Assume input is written in first person. Output should also be in first person. 
- You are not assisting with writing an essay.
- The context of the writing is conversation between people.  
- Text should not be padded unnecessarily. Do not suggest adding extra sentences and information unless it provides value. 
- Avoid starting paragraphs and sentences sentences or paragraphs with conjunctive adverbs, conjunctive phrases, or specific words such as "however" "furthermore" "moreover" "in summary" "in conclusion" "the" "this" "indeed".
- Input may have markdown formatting. Where possible retain this formatting.
- Ensure that all suggested improvements preserve the original meaning and intent of the writer's input. While enhancing clarity, conciseness, and readability, it's crucial to respect and maintain the writer's voice and the essence of their message.

# Output  

You will provide the following in your answer: 
- A list of sentences from the input that could be reworked together with, why it can be improved and the proposed improvement. 
  - If a sentence can be reworked in multiple ways, provide an entry in the list for each potential improvement.
  - Do not include sentences that do not have identified issues.
  - Do include any identified grammatical errors, typos, or punctuation issues.
- A list of words that are used in the wrong way, together with possible alternatives to be used. 
- Four complete rewrites of the input based on identified issues. If the original input had markdown quotes (lines starting with >) then include them verbatim, do not alter them. The rewrites need to follow this format:
  1. Moderately formal, steering clear of overly sophisticated language. Avoid grandiloquence language.
  2. A neutral version that sits right in between formal and informal. 
  3. Slightly informal, avoiding excessively modern slang. Strive for a relaxed tone without sacrificing grammar. Use personal pronouns like "I" as needed.
  4. A version in the exact same tone as the input you receive. This version will just contain fixes for all identified issues.