I have the RCBS RangeMaster 750 scale. I think it's discontinued & replaced by the RangeMaster 2000? I plug it into a UPS power supply device which keeps its current more stable, never had an issue with it for all the years I've been using it.

Some things to note when using electronic scales:
- keep away from any drafts, air movement, etc. (don't put it on your bench under a HVAC register/vent, for example) Some models, like the GEM, etc. have covers which eliminate the 'air variable factor'
- buy and use a good set of check weights: these are NOT what the scale will come with, they're calibrated pieces of metal that are known to be an exact weight. Use them when recalibrating your scale, or setting it up, and/or periodically checking its 'zero'
- make sure the power supply is as stable as possible
- be sure to place on a stable, level surface and try not to move it once it's setup!