What's the difference between buying a character and adopting a character?

Its the same thing really
Your buying a character that was already made
I cant really say the absolute difference between the two cause the definition most likely varies between artists

For me they are the same thing just that adoptables are more template based so they can have the same pose and body structure but be different in species and designe so its easy to make more of them with less effort. Not to say that adoptables cant be unique and different from one another, as there are some artists who put alot of work into an adoptable, some even exclusive to that artist.

characters are something that the artists (or the account owner i guess for non artistic people like myself lol) have used for a while or at some point for art or commissions and the like so they may have a bit more sentimental value, like my character Krissy on my other account, she used to be the sona of one of the artists here on FA. So shes not an adoptable since she was made for the purpose of being her sona.

lol sorry for being long winded but i hope that helped lol ^^

It does. I just don't really get why people adopt.

I suppose its just that if you see a designe that you like or a character you can get that the artist decides to sell yoi can get them or a pre made character rather then making one yourself, its also a way to get closed species adoptables. Since you cant make tgem yourself cause they are only allowed to be,made by the artist adopting a character/buying one (how ever you prefer to say it) is the only way