After market gauges

[skid]

My daughter bough me a set of After market gauges being boost, pyro, water temp and oil pressure for Christmas, the are Autotecnia brand all are electric anolog in nature, the water temp one and the oil pressure ones in particular when the ignition is turned on and they do their initial calibration do not return to zero mark, the sit around the second black mark on the dial, is this normal and to be expected for gauges that only cost about 60 or so each? I would expect if I had paid big dollars for top of the line gauges I'd expect them to work perfectly and accurately, the reading when running are with in spec, apart from the boost gauge, which if I floor it reaches 8PSI and once or twice I saw it reach 10 PSI, the previous gauges, the boost read 12-14 PSI and the saas water temp gauge always sat on zero when the motor was cold prior to starting it.

The new water temp gauge read about 75 when running with the air con running where as the saas gauge always read 82. The water temp sender unit was stuffed out of the box and the gauge would read all over the place, so I have had to put my saas sender unit back in. Should I be concerned and send them back?

The seller is being a royal pain about it all, and i may have to get Ebay and or Paypal involved... I'm at the very least sending the water temp sender unit back...