Immich - Such a polished piece of software that I couldn’t imagine storing all my images without

Tuta (previously Tutanota) because it’s private, runs on 100% renewable energy, very affordable if you want to use a custom domain, has end-to-end encryption between Tuta emails and it’s email clients are open source including a very nice app on F-Droid

If you really need a computer and don’t have the budget for one that costs $600, then don’t get a $600 computer. There are plenty of old office PCs on eBay that you can get for less than $100 and they should be fine for only homework. Just search for “Office PC” on there. This is not the place to be asking for money, but I hope you find something that fits your budget and that university goes well.