A burden to bear
Reverse Rings and Manual Extension Tubes may be very cheap (~RM30 each), they do not offer electronic linkage between lens and camera body, and of course, they are not very well built. So, you might risk dropping heavier lens (18-105mm kitlens above). If you are really into Macro Photography, automatic Extension Tubes are definitely a better pick!
For more info and guides on Macro Photography, please visit my blog here: pixelsdimension.com/