Recommendations needed on software to correct English grammar

A necessary ingredient to surviving and possibly prospering in science is the ability to write clearly in English. Yet many students are not native English speakers and some have had poor education and training. For some, it is even difficult to write basic sentences without grammar and spelling mistakes.

This is a serious issue for both students and advisors.
Unfortunately, what happens too often is that advisors spend too much time correcting the English in drafts of papers and thesis chapters rather than focusing on the scientific content.
Even, worse lazy or over-committed advisors don't do the corrections and referees, examiners, or editors are left with the problem.

Advisors, co-authors, and examiners can get quite irritated in the process.
Students need to realise they are really hurting themselves in not addressing this issue.

Is there a solution?
I try to encourage students and postdocs to pair up and read each other's drafts. However, this is not really quid pro quo (i.e. a fair transaction) if one is a much stronger English writer than another.

A colleague recently told me about a solution he found worked very well. His institution bought the Grammarly software for a graduate student, who was excellent in science but poor in English.  Before giving any document to the advisor the student had to run it through the software. This not only finds spelling and grammatical errors but suggests alternatives and gives the reasons for the error.
Thus, it not only corrects the errors but trains the students. It does work. The student can now write better even without the software.

There is a free version of the software that has limited capability. The premium version costs US$140 per year. You can buy just 3 months for US$60.

I downloaded the free version to test it. It found a few minor mistakes in this blog post! I also tested it on a student essay and a weekly report. It found some errors, missed a few, and pointed out that there were several errors that could be corrected with the premium version (very clever marketing!).

Does anyone else have experience with this software, either themselves or getting their students or postdocs to use it?

Unless they are at a poor institution in the Majority world I think faculty need to bite tell students they need to buy the software.
If students are serious about getting a Ph.D with less stress and keeping their advisor on good terms they should buy it.
In the grander scheme of things this is a small amount of money.

I welcome recomnendations on alternatives.

On the lighter side do a Google image search on "funny English signs"