There are many types of fashion shows and many ways to attend them.
I’m sure LA has a couple of city magazines. They usually throw annual fashion extravaganzas based around fashion week. Call your local magazines and ask when their next fashion event is.
There should also be a number of different fashion design schools in your area. The students will have shows a couple of times per year. They are fun.
There are dozens of modeling agencies in LA too. Call the agencies and ask when the next show are booked for.
Your local shopping mall probably has some events too.
Prices vary from big dollar to free. Depends on the seating you choose and if it’s affiliated with any charity dinner. Usually, Fashion Week events are free, but you have to get there in time.
If you’re really into fashion, then call your local modeling agencies and ask for a list of local designers who participate in shows. Then call the designers and offer to help out. You’ll get behind the scenes where the most fun and action is. Tell them you’re an amateur photographer and you can provide services for free pictures.
You can also get a list of fashion photographers from modeling agencies. Ask which ones cover the shows and call them to assist.
Just start poking around. It’s going on all the time.