When NCAT was set up, there was an attempt to make it lawyer-free or, at least, not assume that lawyers would be needed, but allow lawyers to represent clients by mutual consent. That seems to have drifted somewhat, with some Members reportedly frustrated that they have to explain procedures to one or other side of a dispute.
In any case, if you win, under Section 90 of the Act, costs can be awarded against the other members of the owners corporation, excluding you. And they have to raise the money by a special levy that you don’t have to pay. However, I think you have to ask for costs to be awarded at the start of the proceedings as the default is that each party pays their own costs (which would, indeed, mean you were paying to take yourself to the tribunal).
If the Owners Corporation has lawyered up, it might be worth you getting representation too (especially since your grasp of strata law may be based on flawed assumptions … e.g. you weren’t aware that lawyers are allowed).
If you can’t afford an experienced strata lawyer (and there’s no point in employing any other kind), Marrickville Legal Centre will provide free legal advice and even, in extreme cases, representation at the Tribunal.