Compliant Actuators differ from traditional Servo Actuators via the ability to sense and control for forces, in addition to position and velocity. A multitude of concepts exist: force-torque control of brushless DC motors, Series Elastic Actuators (SEAs) featuring a physical elastic element, and Variable Stiffness Actuators (VSA), which use a stiffness control mechanism to modulate the physical stiffness of the elastic element. However, due to the complexity, variety, and prohibitive cost of parts and fabrication, there is a lack of reproduction, which hinders the, development, adoption, and application of such devices. This paper introduces the concept of a Modular Compliant Actuator Toolkit (MCAT), intended to facilitate cost-effective design, control, fabrication, and testing. The MCAT comprises of 3D printed panels and parts which assemble to form a box-shaped compliant actuator, using off-the-shelf components, supplemented with associated hardware and code. By identifying the challenges pertaining to the research and development of compliant actuators , and segmenting them into discrete aspects of the MCAT, a user can focus their efforts on their specific research, without the upfront cost of time, labour, and finance. Additionally presents on-going progress towards a low cost SEA prototype, and discusses the lessons learned from development.