Carbon monoxide alarms......so expensive for the HOH or deaf GEE WHIZ

I will be using propane in my van for heat and cooking. So I need a reliable detector for carbon monoxide. Theres plenty out there for larger homes /families with deaf and non deaf people out there. Really in my search theres not a lot out there for single people who just want a light strobe and runs on batteries. The one that looks promising is this
 http://www.marilynelectronics.com/SafeAwake-Fire-Alarm-SAFEAWAKE-p/hc-safeawake.htm?gdftrk=gdfV23318_a_7c1154_a_7c4507_a_7cHC_d_SAFEAWAKE
Now i know you have to plug it in and yes it will cost you your arm and leg but we are talking carbon monoxide here. The silent killer..so we can't play games with this. I'll try to cut costs else where where it is NOT important.
But this is not the end. I'm still looking.

Bed Shaker

In my quest to find gadgets for the deaf I realize I won't be able to use my light alarm. Its just a timer which sets my light on at 4 am in the morning. Its has a 100 watt bulb in there and thats too much light for a van dweller.So Im looking into this
http://www.amazon.com/Silent-Vibrating-Personal-Alarm-Shake-N-Wake/dp/B0027A573Q/ref=sr_1_17?ie=UTF8&qid=1317842823&sr=8-17.
I'm ordering things way before I move into my van so I can do testing. Doesn't hurt to be careful. If anyone ever used this please be kind and let me and everyone else how it works.