A low-cost, straightforward, rapid prototyping of whole-glass microfluidic devices is presented using glass-etching cream that can be easily purchased in local stores. A self-adhered vinyl stencil cut out by a desktop digital craft cutter was used as an etching mask for patterning microstructures in glass using the glass-etching cream. A specific calcium-assisted glass-to-glass bonding at 115 degrees C in a standard laboratory oven for 2 h was used to complete the whole-glass microfluidic device fabrication process. Various functional microfluidic devices were demonstrated with this rapid prototyping method. The complete fabrication process from device-design concept to working device can be completed in approximately 3 to 4 h in a regular laboratory setting without the need of expensive equipment and the need to handle extremely hazardous hydrofluoric acid. This whole-glass rapid prototyping method will be of immediate benefit to the microfluidic and nano- or micro-fabrication community in potentially saving time and costs associated with prototyping of whole-glass microfluidic devices. Also, it lowers the barriers to new entrants to the field of microfluidics and could be useful at both undergraduate and graduate levels for hands-on microfabrication and microfluidic courses with limited resources for expensive and high tech equipment. (Contains 6 figures.)