By law, a glucose meter must read accurately within 20%- that means if you take a reading and it is 100 - the true amount of glucose can be from 80 - 120. If your reading is 200 the amount can be between 160 and 240.
Now if you stick two different fingers at the same time and take readings you will get 2 different numbers too. Warren has mentioned a study that showed certain fingers routinely give higher readings than others.
Your inexpensive meter was within the 20% allowable deviation. Meter readings rarely show the exact amount of sugar in your blood. They show the amount of sugar in the sample within 20%.
Many meters throw an error if not enough blood is loaded onto the strip. My one touch meters (Ultra2,UltraMini, and UltraSmart), my precision XL, and my Ascensia contour do the same.
Soap, handcreams, food residue, excess moisture and alcohol can all give you a bogus reading.
I test frequently, use the results to look for trends in my readings, and compare my averages to my A1c results to determine how well I am controlling my sugar levels.
Here's an example- my AM fasting reading is usually between 80-95. Several weeks ago, I noticed that it had jumped to between 100-115, so I called my doctor- I thought I might be having some allergies but she had me come in 2 days later- lo and behold I had a sinus infection, a bladder infection and a kidney infection and was dehydrated to boot- those AM numbers stayed there until the infections went away. Fortunately, they are back down to the previous range although I was warned that it might not happen.
So- don't worry about your meter too much- they all have to be in the same lousy range sandy
I just want to live happily ever after-every now and then. Jimmy Buffett