I looked into the 2 you mentioned from amazon before. I decided to stay away, waste of money. The thumb leads are useless. The forearm leads amount to only a single lead trace. IMHO, that is probably not enough resolution to make a diagnostic-level trace. Medical grade equipment designed to pick up diagnostic-level traces will have 12 leads.
You might want to try ebay. I've heard of folks finding used medical-grade EKGs there for pretty cheap. You might be able to pickup a 12 lead for pretty cheap.
diagnosing afluter versus afib on a medical grade 12 lead EKG is hard enough, I really doubt a mickey-mouse EKG can pull it off. There was a nurse on one of the reviews who mentioned even the forearm leads were not picking up PVCs. Holy crap, a PVC will make for the most bizarre QRS wave you will ever see, if it can't pick that up there's no way it will pick up the minutia of a saw tooth pattern of afib or aflutter.
Jerry_NJs comment above got me searching a bit more. There are several personal EKG units on the market that will create printable strips on a PC. They can be bought on Amazon.
The ReadMyHeart and Instant Check by DailyCare got reasonable reviews:
http://www.amazon.com/Readmyheart-Personal-Handheld-illustrator-Electrodes/dp/B0010AN63W/ref=sr_1_3?ie=UTF8&s=hpc&qid=1262107424&sr=8-3
http://www.amazon.com/Portable-Handheld-Real-Monitor-InstantCheck/dp/B001FAJP2I/ref=sr_1_9?ie=UTF8&s=hpc&qid=1262107424&sr=8-9
Here is a review of these units from 2008 (there are lots of good links in this paper):
http://www.cardiacdirect.com/brochures/ECGMachineComparison.pdf
Anyone know if these personal "low cost" machines will work for monitoring/diagnosing A flutter and A fib?
Ouch on the charges for the monitor. That seems to be the device best for catching a record (strip) of you problem.
I know the long term monitor can be expensive, I wore a Cardionet (Registered Trade Mark, I think) and it was covered by my insurance. Still it cost me over $250 out-of-pocket. Clearly you need to be sure the device supplier/service is in-network - I think it can be done.
To your question, I think I have seen some discussion on DIY EKG... have you done a MedHelp and Web search?