I picked one up last year, and it works great!
http://www.canadiantire.ca/AST/browse/4 ... Reader.jsp" onclick="window.open(this.href);return false;
The only odd thing it that it woudn't detect a connection on Kp2t's dad's Camaro...weird.
This is an OBDII code reader, so it will only work with OBDII Mx-3's. Your 95/96 will probably be, but if it's a '96, it was mandated by the gov't that all cars 1996 and later must be OBDII, 95's are likely to be, but not 100%.
Your 93's are not OBDII, so no code reader will work on it. There are OBDI readers, but they aren't typically Mazda compatible, and I know of none that exists. The only option is the good ol' paperclip in the diagnostics box.