Alarm/Remote Questions, 3 Way +

I've got a 98 Mercury (Mistake) Mystique that needs an Alarm system. Because I'm a cheap basturd I'd like to stay around 150$ Max if this is possible. I'm not really sure what Alarm I need to buy. There are those cheap 80$ units that come with cheap remote keys and fall apart in one years time, not sure I want those. Then again, I'd need something you could run a car over (Mad Wife) and have 4 kids jumping on it (Insane Kids) without a scratch.

The reason for this Alarm is because my wife put her purse in the trunk while at church thinking that was safe, but left the window cracked open. Someone slipped in, popped the trunk and ran off with her stuff. You know the rest, cops reports, credit cards, banks all closed with fees for everything lost ect..

Anyway, on to the real questions.

"Door Lock 3 wire(+) WHITE/ Green Left Kick Panel"

My question here is the "3Wire(+)".

https://www.the12volt.com/doorlocks/doorlocks.asp

" There are three wires in the harness not counting the illumination wire(s), if any. One wire has constant (+) 12 V DC at all times. Another wire only shows (+) 12 V DC during lock and ground at rest. The last wire only shows (+) 12 V DC during unlock and ground at rest. "

https://www.the12volt.com/doorlocks/page3.asp#3wp

" his is one of the most common type of door lock switch configurations found in most vehicles. In most cases you will not need to add relays for this type. Most of the newer alarms and keyless entries on the market today have both positive and negative 200 ma door lock outputs that are usually capable of activating the factory relays. Should you need to add relays for a "3 wire negative" door lock system, just change both normally open terminals (87) from 12V(+) to ground. If your alarm or keyless entry has positive outputs only, you will have to connect the other side of the coils to ground  and connect your outputs as shown. The lock and unlock wires below refer to the switch leads, not the motor legs. "

I don't think this is really a car that people would take. It's a baby light blue color and has a girl feel to her. 

Do I need an Alarm system that has Poss. or Neg. unlocks? I was looking at those crimestoppers and they listed "Neg(-) only, so I'm lost now on what to buy. So I need your help and thoughts on this matter. Thanks!

It dosen't really matter what the alarm outputs, most are either negitive or reverse polarity. IN any case you have to use a relay  it changes the polarity for you. Your switchs are postive triggers from the drivers kick panel WHITE/ green for lock, YELLOW /GREEN for unlock. If you get the crimestopper alarm which is really good by the way,  you hook it up to the relay and it switchs it to + and provides the adequte power to power it.

Let me know if you need help

Are there any other brands that have possitive unlocks or built in relays?