Depends on who you know- some female riders got great deals off fellow riders, parts and frame wise; wouldn't jump into completes right away as they are usually very hard to sell 2nd hand.
look for short t.t frames if you are just starting out, if you have some experience and looking to link tricks up, longer t.t. Lengths will be more suitable.
weight- what type of rider are you? Heavier you are, heavier the frame has to be, ditto parts wise. For parts you might get away with titanium/ alloy upgrades to the spindle, hex nuts/ bolts and spokes.
forks- zeros if you plan on running short t.t frames; crank arm lengths get critical when there's minimal room between b.b and front wheel.
cranks- 145mm or shorter if t.t length is 17.9" or lesser.
bid your time with your bike built, especially when on budget, choice parts will come on gflat for a song, just gotta be quick.