If you live in the US, the Relion Confirm or Micro meters from WalMart are what most of us use. The strips are a lot more affordable than the AT ($35.88 per 100) and you can get strips pretty much 24/7 if you need them
The Relion Prime has cheaper strips, but takes a larger sample size and some people complain about frequent error messages.
You can't convert a human meter and pet meter numbers....there's just no "formula" for it (and lots of us have tried!)
The important number is the low.....under 50 on a human meter is your "time to act"....on the AlphaTrak, it was 68
The higher the number, the more it can be off.....but if it's too high, it's too high, so it doesn't really matter if it's 300 or 400!