Best apps or you tube videos for learning Italian

I've used many. I think probably the most useful for me for a foundation was Coffeebreak Italian seasons 1 and 2. It's available for free as podcasts or online you can access each of the 40 lessons per season. You can pay for a subscription and have access to additional materials, but just going through each episode was very helpful for me. I've replayed them many times.
For apps, I've done duolingo for 5+ years, but it won't teach you things like grammar, it's better for remembering things you've already learned and for vocabulary. I'm also using BUSUU app on my phone, I think it's better than duolingo for more authentic voices and sentences.
If you want to sit at a computer and do more of an academic, rigorous course, check out Wellesley edx courses, they are free or you can pay to have your lessons graded and earn a certificate. I've done Italian basic and am working through intermediate (again!).

October 1st is in about 225 days. So the decision you need to make is how many hours you want to spend on this and what you mean by "decent foundation". You can read a paper by Cambridge Press on learning a 2nd language at https://www.cambridge.org/elt/blog/wp-content/uploads/2018/10/How-long-does-it-take-to-learn-a-foreign-language.pdf My guess is you're describing a B1 or high A2 level as per https://en.wikipedia.org/wiki/Common_European_Framework_of_Reference_for_Languages An estimate from the Cambridge article is it would take around 200 hours to get to A2 and around 400 hours total to get to B1.

The linguist John McWhorter recommends a paid product, Glossika (article behind NYT paywall at https://www.nytimes.com/2021/09/14/opinion/learn-foreign-language.html) A somewhat similar product he suggests is Assimil which is less expensive (see https://www.npr.org/templates/story/story.php?storyId=5021582 )

However neither of these is for an absolute beginner. I suggest starting with Pimsleur which comes in sets of 30 half-hour audio lessons. I don't think they sell the course anymore (and when they did it was pricy) but you can often find them at a library. You might want to do the first 3 levels (90 lessons) which would take 45 hours and then start one of the programs mentioned above. And maybe Pimsleur is all you want; a few years ago I did just these courses and then we did ok travelling in parts of Italy where English isn't common such as the Adriatic side. Didn't know anywhere near enough to have conversations but enough to handle standard tourist interactions in Italian.

If you want something closer to a standard class but self-taught, either as a supplement to the above or as your main methd, then the Great Courses has a class that is supposed to be equivalent to a first year Italian class at college and it's taught by a college prof. Their courses are expensive (although regularly on sale) but if your library has Kanopy you can watch all the videos free and the Great Courses will sell you the workbook for just $10. See https://www.thegreatcourses.com/courses/learning-italian-step-by-step-and-region-by-region

I used Pimsleur audio for a foundation along with classes at my community college. It gave me a good head start when we started traveling to Italy 13 years ago. Pimsleur is great in the car during your commute.

Mango is an online language learning app that many public libraries offer free access to with a library card.

I've done three things over a few years: Pimsleur CDs in the car while driving; Duolingo lessons every morning; and local community education classes. Taking a class is good, but only if your teacher is experienced and your class actually takes it seriously. You can only go as fast as the slowest person.

But I think it's mostly about how much time you can afford to put into it, and when.

My Italian teacher has a YouTube channel (https://www.youtube.com/@teacherstefano) that offers free videos with a mix of grammar content of varying levels and practical advice such as how you would order at a restaurant. Stefano is really engaging and is good at explaining things.
I also like Easy Italian on YouTube. There's an app called HelloTalk where you can write and talk with native Italian speakers who are learning English. Like any social media, HelloTalk can be hit or miss, but it can provide a good opportunity to practice conversation for free. iTalki is another website where you can book lessons with teachers or conversation practice.

I also have used Coffee Break Italian. Loved it & felt it gave me a good foundation. You have to put in the time though & keep up with it.

I tried Babbel for German a few years ago and wasn't impressed, although I think the technical side of the service was fine. I'm also prepping for Italy in the Fall, and Mango is the first thing I intend to try. Your local library should have a number of resources available at no charge. And some of the YouTube resources mentioned above look interesting.