there are a couple for sale here in the classifieds. if u dont want to spend 650 for a termlab. but if ur gonna buy one i would spend the money for a termlab
The walmart and anyother little handheld meters measure on a weighted scale and will not give you an accurate measurement. They can be 10 dB off on high frequencies and 20 dB off on low frequencies as compared to the meters we use in comps like the Termlab or AC 190.
Also, their peak is 130 usually. They are microphone based with a cheap mic, I have broken many of these mics in the past.