Hi,
Welcome aboard, I am also new to tigers and have been through the headlight problem just recently.
I bought the Triumph relays at £27 for the pair, but I have since found TriumphTiger-online are doing them for £12/pair.
I have also seen them on Ebay under Triumph Tiger.
Be warned, ordinary relays will drain the battery when the ignition is isolated. You must get them with diodes in and in the correct location as per the Hella ones (Triumph uses Hella).
Fitting them is a doddle, just remove the near side black plastic cover that the indicator mounts on, pull of the rubber cover and plug in. Then replace all.
Another common upgrade while your at it is to change the bulbs to Phillips Blue Vision or something similar. Downside is they cost over £20 a pair.
Chris
Below are the links
Dual Headlamps
Triumph Tiger Online