Does buying the head texture item for 2,000 TC in the store, am I buying a single texture? Can I only upload a single texture and I'm stuck with that head texture forever? Or can I upload a new one whenever I want to change it? I guess the same question applies to every texture. Thanks.

You can change it whenever you want

yea just go on the texture link on the sshop down the side and uploads something else once your bored and i would suggest buying from the forum you might get it it for like 1k