Wanting to learn more about varying radon readings in the basement and living areas of the house, I came across this item at Amazon:

linked

which monitors radon levels continuously with a display type reading.

We had a quick test of 7.8 in the basement and I've learned that a single reading is insignificant as there are many variables (mostly weather and seasonally) that can be significant. Of course, because of the reading that was above 4.0, we've been encouraged to install a mitigation system with all the bells and whistles which will cost thousands. Keeping a window open in the basement might be just as effective.

Anyone ever use something like this meter or have a suggestion on how to monitor radon levels?

The Sep. 2008 Consumer Reports has a review of radon testers, and the short-term testers (2-7 days) varied a lot in accuracy and reliability. The best were:

RTCA 4 Pass Charcoal Canister, $20: accuracy B/reliability B
First Alert Radon Gas Test Kit RD1, $22: C/B
Air Chek Short Term Radon Test Kit, $10: C/B

A $120 radon meter, Safety Siren Pro Series 3: C/B

The long-term testers, which required 90 days of exposure, were generally better than short-term testers:

Accustar Alpha Track Test Kit AT 100, $28: A/B
RSSI Alpha Track Long Term Radon Test AT-101: B/B
Pro-Lab Long-Term Radon Gas Test Kit RL116, $40: B/B

It shouldn't cost too much to reduce radon levels. The best is usually negative pressure, which uses a big plastic pipe driven into a hole that goes below the level of the basement floor, and has gravel around it and a fan at the top of the pipe top to suck up radon and exhaust it outside. Several of my relatives in Illinois have this. I'd aim for less than 2 pCi/L.

Not sure if anyone is still checking this post, but I actually bought the Safety Siren kit and have been using for a few weeks now. It has maintained a level of around 13 in my basement, which is concerning to say the least. I just stripped the drywall off my cinder block walls and some of the tiling from the floor, so that definitely could be hurting us. The gas comes up through the floor, walls, drain holes, sump pits, etc....

I plan on installing a mitigation kit myself in the near future. We have only lived here for a few years and rarely spend time in the basement. It is a scary thing though to learn about Radon. I highly recommend the Safety Siren system. Pay $120 or cheaper through eBay and have it for life. You can move it all around your house and not pay $20- $30 per test. Good luck!