YY BY-18 Electronic Flash (5600K)

Pros: Cheap. I bought 3 of these for practicly nothing, I use them together with the remote trigger SKU 8201 for some experimental flash usage.

Cons: Build quality is really bad, they work fine though. Should only be considered for trying out some flash ides, not for "normal" everyday use.

Other: I wanted to try out some "off camera" flash ideas and needed multiple light sources, doing it the proffesional way with Nikon flash units and pocket wizards for remote triggering would have cost me hundreds to thousands of dollars.
This setup is not as reliable and there is only one power level but for experimentation you can save huge amounts of cash.

Pros: Works great with the Seagull remote Slave Trigger (SKU 02321) and any of the cheap little tripods offered on here for a little improv, off camera fill flash. It's small and light weight so it doesn't take up much extra space in the camera bag.
I actually bought this as a "hair light" flash so the fact that it dumps it's full flash doesn't cause much of a problem for me in terms of light but it does result in a delayed cycle time compared to my speedlight or any higher end flash. A good set of lithium batteries helps with the cycle time, though.

Cons: Make no bones about it - this is a cheap flash. It feels cheap, looks sort of cheap, doesn't come with any swivel and the only adjustment to the flash itself is power on or off. I'd be afraid to mount this on my camera for fear of hurting the camera. I knew all of this when I bought it so I wasn't disappointed.

Other: Buying a cheap flash to put on an expensive camera is just asking for trouble. Don't do it!
That said, this product is a good value when used appropriately.

Pros: Cheap, small, lightweight flash.

Cons: High sync voltage! (70 volts), this will fry many cameras if connected directly, search around online or check your cameras manual for the max voltage flash you can connect, or use some kind of remote trigger. My camera can handle a couple hundred volts, fortunately.
No control over flash duration.
No swivel or tilt.

Other: Seems to be a decent flash for the money, I just wish it had a dial to control the flash duration.
I bought a few of these because they're cheap and small, so I'm not worried too much if I manage to break them.
Good price for what it is!

Pros: - small and very light weight - work with slave units perfectly (SKU 8201) - a set of four with slave triggers is enough to light up a fairly large room when using an on-camera master flash aimed into the ceiling - cheap (four flashes and four slave triggers totaled at the time of my order to less than 10 €/set) - so cheap that you won't go bankrupt of you forget one or two on location - takes only 2 AA-sized NiMHs

Cons: - power level is not adjustable (but this can be worked with by changing flash distance, etc.) - sync terminal voltage is too high for use on Canon bodies (around 70 V), but with Nikon you're fine on most bodies that allow up to 250 V sync voltage

Other: Cheap, effective solution for quick lighting. Most flash power per buck I've ever encountered.

Pros: Compact - most likely it will appear smaller than your camera and fit your pocket just fine.
Lightweight - only 170 grams when loaded with 2*AA NiMH rechargeable batteries (32 grams each) and equipped by SKU 8201 remote trigger.
Quick - recharge time is only 3...5 seconds depending on batteries' voltage.

Cons: Is not adjustable in neither way, so the best use for these flashes is equipping them with remote triggers (once again: look at SKU 8201) and putting them on a separate holders (like SKU 1309) for lighting away the shadows produced by your on-camera flash.
Also, the fixing nut looks weak.

Other: If you need secondary flashes - these are a good choice.

Pros: Very cheap for a flash, even a non-adjustable one.
Nice addition for "Lomo" cameras like the Holga/Diana/Blackbird Fly/Golden Half etc
Very powerful (more than I wanted actually)

Cons: For the price there are no real cons but if I had to list a few:
Not adjustable
High sync voltage (not safe for digital cameras)
No slave

Other: Handy if you need a cheap external flash.

Pros: price and build qualities are perfect. I am not expert but bulb in the flash is new generation not old type. load speed is very fast <3sc. it is best for diy studio photographers. with a trigger and mini soft box (sku 37666) getting diffuse light is simple. may be you can modify the flash and inseret a dc cable for indoor use only.

Cons: Actually it's a analog flash not suitable for DSLR type cameras. when you put it to hot shoe Camera will not see the flash. so when you select the camera's flash to on, it just pops up build in flash only.. syncro voltage not suitable especially for Nikon d90.

Other: I recommend this for especially indoor studio photographers. simply cheap and working as a studio flash.

Pros: - Cheap for its quality - Really fast to load - Powerful!

Cons: - A bit big and heavy - People get scared when notice the big flash attached to the camera!

Other: It's a lot cheaper than regular flashes for film toy cameras and works perfectly!

Pros: very light, uses just 2AA's and gives a pretty decent power. It has about 1/4 power of my SB700 and it costs under $10! Combined with 8201 it will work with any camera that can shoot manual flash, giving you a cheap, light, off camera flash for under $15.

Cons: It doesn't have any power control, so you have to set it up, and then change aperture, ISO or the flash-subject distance. If you can live with that it is the cheapest lighting solution I know. Use on-camera is not recommended since you don't know the voltage it works on (old flashes used high voltage that could harm your camera). If you need TTL or even to manually alter the flash output you will need something a little better. Also, since it only takes 2AA's the recharge is not too fast.

Other: awesome setup for an off-camera flash but be ready to use all your lights on full manual.

Pros: The best "pro" for this flash is the price, you can't get a cheaper flash. It charges up pretty quickly, but you can't except that it will be the same as some expensive flashes. It comes with a nice diagram to check your settings on camera, yes the whole thing is manual.

Cons: For me it has no cons, I hope the flash light will work for a long time. Maybe a build quality could be a little better.

Other: If you are in photography as a semi pro or a professional is logical to buy a better flash. But to use this flash on old film cameras, now this flash is a good buy.