dear people using the internet to sell, impress, or get a date:
please realize that your basic spelling/grammar skills are going to be criticized and if you don’t HAVE any basic spelling/grammar skills, please get some or stay off the internet. I will demean your intelligence and/or not buy anything from you if you can’t present yourself in a professional manner and at least SPELL or know how to USE basic words correctly.
your = possesive belonging to you. “i’m looking at your cat right now.” it is your cat, it belongs to you.
you’re = you are. a contraction. don’t use your in place of you’re. it makes you appear dumb.
their = possessive belong to some bunch of people not including you. “i’m looking at their cat right now.” the cat belongs to them.
they’re = they are. a contraction.
there = a place. over there. somewhere over there.
for all other spelling issues please visit dictionary.com