I own 2003 Toyota corolla CE. My car insurance is pretty expensive and I was told that the installation of signal systems will help reduce my insurance. But I do not want to alarm can be set easily from the voice of the people.

As the poster above me said, check with your insurance company to find out if there's anything they do or don't cover. BUT, because Toyotas of pretty much any kind (along with Nissans, Hondas, etc.) are a hot car, they're going to have high theft insurance. My advice would to be to consider an ignition kill alarm (where you need your key to start the car) or something like Lo-Jack - but that can be pricey.

I want a car alarm system that is $150 or less that makes cool noises such as "chirping" when you lock and unlock the car and makes cool siren sounds when the alarm goes off.. Any good ideas??

First off, $150 isn't going to get you a decent alarm with the install.

I would go to www.viper.com and look around there for pricing and custom build your own alarm from their site.

A basic alarm will work but you really need to get the battery backup add-on and possibly a second siren with a separate battery back-up. Possibly a tilt sensor so thieves don't just tow your car away. Each of these add-ons cost $70-80 from Viper.

Chirps and cool sounds aren't what you should be considering. But Viper alarms do chirp if you set off the alarm accidentally but the siren noise is standard. If you're into the cool factor, there is a $199 upgrade where the alarm will say "Intruder alert" and other phrases which you may enjoy.

If you really only have $150, don't get an alarm but get a fuel cutoff switch installed. What that does is turn off the pump that sends fuel to the engine. Kind of difficult to steal a car that can't move, ya know?
Parts and install for just that will run $80 at a good shop.

With the cutoff switch, a basic alarm with battery back-up, you really can't go wrong. But you're looking at maybe $600+ with install. It is a small price to pay, trust me, it's worth it.

Where I come from:
I've had one car stolen ('95 Honda del Sol) and someone attempted to steal my current car ('99 Honda Civic Si) last week. The del Sol had a basic alarm with no battery backup or sensors. The Civic had a cutoff switch with a basic alarm. After doing some more research, battery backup with a second siren AND the tilt sensor added to the alarm with a cutoff switch is really what a basic alarm should come with.