Fuck what anyone else think mate, if you can do it go for it. 99% of people spend a lot of time complaining about everything, let them alone with their protagonist syndrome.
Nothing exactly, you can make another account on other instance using the same email. And as it is pseudo-anonymous you can always use a new email and other username and no one will know you are the same person.
I have bought several used hardware at local marketplaces which are working like a charm, it depends if you know about what are you looking for when you buy.
My recommendation would be buying a used HDD at a local online marketplace, if you want bang for the buck, if you don't, then buy a SSD from AliExpress(important to check reviews)
There is like 40 apps