No you can still buy used games if you want to pay for a 10 dollar code.
You only need to put the code in once. It stays active on your account forever.
every time you buy a new game
Obviously only once but a serial key for
consoles is just stupid considering you have to play with the brown townog sticks to enter it in.
To get a normal strong serial for wide audiences you have to use a long key with lots of variations, which of course will involve you having to twiddle with brown townog sticks.