Just to add a different thought. You could also get a 2x and extension tubes rather than an additional lens. I don't have the 120 makro which is also a great choice. A very sturdy tripod is a must. But you can take still life with any lens depending on the space you have to work in and the effect you wish to get. Just to see how they would stack up against each other, I recently took a still life with my 150, 250 and 350 just moving the camera position to keep the field the same. I adjusted the exposure time and f/stop to accommodate the different focal lengths. The resulting prints are identical and you can't tell which lens was used.
As mentioned the extension tubes will get you closer and depending on the tube/lens combination an exposure compensation may be necessary.