I'm new to flashes, and i just bought one off eBay, but its says it wont use th e TTL (what is it?) function or something, so it will only work in manual mode, so will i get the same results considering it works?
eTTL is a method by which the camera meters the amount of light it's seeing from the flash and shutting it off when it's assessed that it has enough light to give a correct exposure. TTL stands for 'Through The Lens' - not 100% sure about the 'e' bit.
Without the eTTL signal from the camera, the flash will just give the maximum amount of output based on whatever settings are set on the flash itself. In effect, it's up to you to work out what settings you need for the situation in front of you. Whilst there is a learning curve to this, it's perfectly possible to get acceptable results, and people were doing just that for years before eTTL existed.
If it says it won't work with TTL, than that means you'll most likely need to manually dial in the power every time your subject changes distance.
It's no biggie if you have tons of patience or are using it off camera, but otherwise, it's a huge time waster and just gets in the way.
A little research before purchasing goes a long way.
TTL means through-the-lens, so if you have eTTL, than that means the flash exposure metering is metering the light through the lens and is automatically adjusting the power. without it, you dial it yourself, which for the most part is not fun.