I don't have a dSLR at the moment but am planning to buy one. Wanted to know the cheaper methods to shoot in macro. Will using macro filters and extension tubes concurrently increase the efficiency of the shot?
Yes, they will both increase the macro effect of the lens when used together.
However, it's not certain that all combinations of lenses, tubes and closeup lenses work together. An extension tube is constructed to be used with a lens without a closeup lens, and a closeup lens is constructed to be used with a lens without an extension tube. Each adds a bit of distorsion, so when used together you may get much more distorsion than you would get from using a longer extension tube or a stronger closeup lens.
First, there is no such thing as a macro "filter". You probably mean a closeup lens. It may look like a filter at a distance because it mounts on the front of the lens like a filter does, but it is actually a single-element lens. Basically, it's reading glasses for your camera.
Second, there is no way to answer your question because "efficiency" makes no sense here. Efficient in what parameter?
It is possible to use extension tubes concurrently with a closeup lens. My main worry would be reduced optical quality, but that is higly dependent on the lens and the closeup lens. In general, closeup lenses usually reduce optical quality because they add yet another element to your overall lens, and the chromatic abberations of this lens can't be corrected by other elements.
Extension tubes have their own issues. There will always be some reflections off the inside walls onto the sensor, and it is using the lens in a way it wasn't designed for. I have one extension tube and lens combination that causes quite visible haze in the middle of the picture. Another drawback of extension tubes is that they don't generally pass thru all the communication (mechanical and electrical) between the camera and the lens, or they are very expensive if they do. At that point, you might as well buy a deliberate macro lens.
So the answer is that there is no general rule what works best with your camera, your lenses, and how you like to take macro shots. Experiment and see what works best for your setup.
Yes, macro photography can be done by using and combining multiple cheap methods (diopter rings, extension tubes and reverse mounting lenses) and here is an amazing example of what Alexey Kljatov achieved by reverse mounting old lens to a prosumer camera.
Edit: Adding diopters, extension tubes and reversing lense changes it's characteristics, where the image is created, what is the magnification of the image, etc. For example if you add diopter to a lens, you can imagine it as "a new lens" with "new characteristics", that's why when you add even more extensions you can imagine them being added to that "new lense", changing it's characteristics even further.
Usually modifying your lens with various attachments could come at a price of quality, so if you are interested you can examine this experiment made by Wayne Schmidt. At the end you can see example of diopter and extension tube being combined.
P.s. If you want to check out how it looks like to combine two extension tubes I recommend this video by ZY Productions.
Yes and the only loss in image quality will be due to the filter/magnifier as the tube/s only add a few cm of air to the light passage and air doesn't have any effect on light.
A lot of DSLR also have a digital teleconverter that you can use in conjunction with your tubes and filters/magnifiers.
I have a Sony SLT-a77 and a $130 tamron 70-300 macro zoom and a $300+ Tamron 90mm f2.8 1:1 dedicated Macro lens.
The tubes don't make a lot of difference when used with either macro lens but they have a massive difference when used with the kit lens