Are cheap and cheerful slave flashes any good?

[vexed]

Hi all
I'm interested in getting a cheap (up to £50) slave flash to use with a Canon 1200d. Are the cheap bits of kit any good or would it be a frustrating waste of a few quid? It would be used for family portraits and maybe playing with other objects...

[vexed]

Thanks, all really interesting insights and I've looked at the models mentioned. I suspect i shall be using the flash remote from the camera. I'm trying to work out what my options are. The 1200d is yet to arrive. Am i right in thinking there is no wireless option as standard? So if I would be triggering the slave flash off the onboard unit. Does using E-TTL remotely require extra wireless addons to the flash and the camera hotshoe?
Budget creep is going to punish me here I suspect.

[vexed]

So what would i need to use with the 1200d to take advantage of the built in wireless on one of those?