There's going to be variation from meter to meter, but also from minute to minute. If these three tests all occurred within a couple minutes, then that's quite a gap and probably outside the meters' margin of error range. To give you an idea, on one meter I got 110 mg/dL and on another I got 75 mg/dL. I called both meter companies complaining and they both said that those results weren't outside the meter's accuracy range and that there was nothing they could do for me other than send me another meter. If you tested your blood sugar over half an hour, then it's possible your blood sugar dropped.
Next time, try to test your blood sugar at the same time from the same drop of blood. A side-by-side comparison will be more indicative.
It's possible, too, that the third meter had old test strips or just wasn't working.
You did the right thing by re-testing. If you're unsure, you should test again. In general, though, I try to take the first reading I get because I drive myself crazy otherwise.