My maxima is maKing a really loud growling noise. When I crank it up and accelerate.. In the Pic you can see my muffler is broken and my rear catalytic converter is rusted and my flex pipe is in bad shape... The shop I went to told me it'll be like 1200$ to fix.. Trying to see if there was a cheaper way out? And will these problems cause it to growl really loud? HELP IS GREATLY APPRECIATED..

 

It sounds like they're trying to scam you (all brand new super marked up parts). It looks like all of that is fixable.
The pipes themselves look to be in OK shape, it's just the typical rust out spots.

A little piece can be added in at the muffler. Flex pipe can be patched or if it's shot, replaced (30 dollar part). I can't see the cat and flanges very well, what's wrong with it?

The cat can go if you don't need to pass visual emissions inspection.

You need to stop the rust on floor board or you'll be Flinstoning it.

 

My rear cat in the top left pic.. Where I circled it. There's like a 3 inch gap. I can't tighten it , it's rusted terribly and how can I prevent the rust on the floorboard?

 

You should go to a different exhaust shop. Try a local non-nationwide one. The place you went is definitely trying to rip you off. I went to a local shop to fix some spots in my exhaust when it rusted and separated. They welded the b-pipe in front of the muffler and the flex pipe. It cost $120.

As for a cheaper way, you could pay a fraction of the $1200 and replace your entire exhaust system with non-oem parts...

 

I recently had a new flex pipe, rear cat, resonator and muffler put in by my mechanic for $800. There were multiple leaks and just welding it wouldn't work.

Go to a custom exhaust shop. They'll be more inclined to only fix the problem areas versus just replace everything.