Hi Bill,
On my pickup I used an "Equator" immobiliser/alarm with rolling code remotes, engine immobiliser, shock sensor, LED warning and central locking actuation, bought as a kit from Jaycar. I then added in central locking on all three doors.
I am more than happy with this setup. The whole parts list (alarm and central locking) was less than $100, though you might not find that pricing.
Here's a link to a ($119) Jaycar unit which meets Australian Standards, so you might get an insurance discount:
http://www.jaycar.com.au/productView.asp?ID=LA8970&CATID=&keywords=car+alarm&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=
Installation was quite straightforward; you don't need a Doctorate in electronic engineering; even I could do it.
hth
