A hotshoe flash will work perfectly well (make sure you read your camera manual to find out if you need to turn off a pre-flash).
Just set it on minimum power and either cover up most of the flash with a piece of card, or fit a red gel over the top. A card will reduce the power to the point where it doesn't create a significant extra light source and a red gel will pretty much turn it into an infra red transmitter.
But an infra red transmitter is less than ideal, because it requires (almost) line of sight with the sensor on one of your flash heads, so in some circumstances it won't work.
And a PC adapter/synch cord is very must yesterdays technology - inconvenient and unreliable. Your best bet is a radio trigger, many of the cheap ones cost a lot less than the Chinese IR trigger you found.