In addition to Rayner's suggestions, there are * _parsimonious_ (avoiding excess) * _stingy_ (ungenerous) * _miserly_ (inclined to hoard money) * _Spartan_ (characterized by self-denial) _Stingy_ and _miserly_ are pejorative. _Spartan_ might evince a degree of admiration. _Parsimonious_ is purely technical, a neutral evaluation. A solution to a problem might be described as _parsimonious_, if it is the simplest possible answer. There are many others.