If double taxation is illegal?

then why am i getting taxed everytime i turn around? I mean there is a fourty percent death tax(money you inherate) cant spell that... any way. you get taxed when your paid, taxed when you purchase, and taxed annualy on property. and if you change state some of them make you pay property taxes on your car again in the same year... i hate it. if the goverment would stop greasing so many pockets(other countries included) we wouldnt need these taxes!!!