Radio triggers are pretty much a "knee jerk" reaction to the desire to move a flash off camera, but if you are not around other flashes going off conventional optical triggers like the Wein Peanut will work.
I used a pairs of Vivitar flashes with optical triggers for 30+ years before switching to Canon flashes and I don't use radio triggers with them either. The Wein Peanut slave is cleverly designed to either insert directly into the base of a Vivitar flash as shown on the left above, mimicking the shape of its proprietary plug, or it can be inserted into the end of a standard PC cord as shown on the right above.
Mind you I'm not saying it is a better solution than radio triggers, but it may be cheaper. They only cost $15 and have an effective range of 100':
The Yongnuo 560 II units come with a built in optical slave, S1 mode for single flash firing, S2 mode for TTL firing which delays the final pop of the 560 II until it detects the last pop of the master flash. I bought 4 of these units a few weeks ago and I'm quite impressed with the sensitivity of the slave but haven't used them extensively outdoors in bright sunlight. I do have Pocket Wizards if I need them.
I use the Manfrotto umbrella adapter and the Vello universal accessory shoe mount with my Photek umbrellas.
Currently, I bring 4 speedlights and modifiers for hotel boudoir and location work.
Here's my setup:
1 Nikon SB-900
3 Yongnuo YN-560's
Yongnuo RF-602 triggers (1 transmitter, 4 receivers)
Various modifiers (5-6 umbrellas of various sizes, strip box, octobox, beautdy dish)
Reflectors of various sizes
4 standard Impact brand light stands and a separate boom arm
My cheap kit consists of two Yongnuo YN-460II flashes ($50 each), two Cactus V5 sets ($60 each), and two LumoPro LP604 compact stands (replaced by LP605 - $40 each). I have a Fotodiox 6x8" softbox ($13), Opteka grids (two at $13 each), and a Neewer 24" folding softbox with a flash bracket ($40), all from Amazon. I also have gels, umbrellas, a beauty dish, a dual flash bracket, a boom, and probably more that I can't think of now.
All of my speedlight gear maybe costs a little more than one SB-910. Gotta love it.
