Any experience with wireless flash triggers from ebay?
They can be. I've got a Cactus that works well to at least 75' (I haven't tried it to its rated 30 meters), works with continuous and bulb, and is easy to set up. Around here, I haven't needed to switch to change to anything but the default channel...there are no garage door openers with 30 meters!
You will find a lot of people that think highly of the Yungnuo triggers around here. They are a good option if a person is just looking for a simple trigger to just trigger off camera flashes (as well as the ability to trigger the camera remotely) at a low cost.
I have a couple sets of the 603 triggers and they are a good value, imo.
Finally, you can also find a number of these vendors offering their triggers through Amazon too. If you do not want to purchase through Ebay, or don't want to wait for a shippment directly from HK, you can often get them faster from Amazon, for a couple of bucks more. I know Amazon offers a number of Yungnuo products, and I think they offer a fews others too.
Good deal is a subjective assessment.
Had/have 2 sets of eBay Cactus v2s (had to wait for the "S" model to be more solid with my flashes (Canon/Sigma). Triggering was unreliable as shipped. Research online pointed to the fact the PCB "antenna" trace was nowhere near matched for the frequency (433Mhz), and that a 10.27"? wire addition seemed to work well for others. I did the modification and they became much more reliable (as long as the button battery was strong). Uncommon battery and weak construction were negatives. Still have them, they work, but they are not in my main kit anymore.
The YN RF602/603 and many other "new generation" units work at a higher frequency, have much better build quality, and are attractively priced. Some lines have eTTL/iTTL or pass thru shoes, or are tranceivers.
Do research on the features of each, and user opinions of the specific units
I bought the RF-602's before the RF-603's became available. I recommend the RF-603's over the 602's because they use simple AAA batteries for their transceivers, not a special battery for the transmitter like the 602's.
The Yongnuo RF triggers are camera brand specific - i.e. be sure to order the ones for Canon or Nikon depending on what brand your camera is.
If you want to use these RF triggers with studio strobes you will have to buy a sync cord separately - they don't come with the RF-603's. Normally you will want the Yongnuo LS-02/3.5 Connecting Cable (PC-3.5). If your studio strobes have 1/4" plugs you will also need to buy a 3.5mm to 1/4" MONO audio adapter - stereo adapters won't work.
Have a look at the 'Pixel King' or Pixel Bishop'. The Kings will do off camera ettl/ittl with settings changed from the camera menu on the fly, they also do HSS, groups and can fire studio strobes upto the cameras sync speed.
The Bishops do on camera pass through ettl whilst firing manual strobes/speedlites.
The range is up to 200 metres!
About a half to a third the cost of the PWs.
Don't rule out Phottix triggers.
I have a set of Stratos II 4-in-1's. TTL pass through on the trigger. Rcvr's can be triggered from more than 200 feet away. I have used mine for 8-10 hour days with no misfires or problems.
Others have the Odin system. I haven't plunged to buy a set yet, but will soon. Those that have Odins love them.