Toddler very emotional/tantrums

So I’m trying to figure out different strategies for my toddlers behavior. When she’s doing something she shouldn’t be doing or don’t get her way she automatically SCREAMS. She began doing this a couple months ago. If I say no even in a calm voice she screams. She throws herself to the floor or throws her toys that’s in her hand or around her. I tried firm voice and a soft voice neither worked. I try redirecting her attention else where and lets just say she doesn’t forget easy. Time out don’t work because I can’t even get her into time out. Her behavior will just get worse. So just looking for some ways to get these crazy tantrums to stop. Or am I shit out of luck because she’s only 3.5? Can’t even go into stores without her throwing a tantrum because I won’t let her have a toy or snack every time. She screams when I say no not right now and put it back and everyone just stares like we’re crazy.