For the majority of a micro budget feature I've been working on, I've been using two lav mics plugged into a tascam plugged into a Ninja 2 (which is also plugged into my Sony a99 camera).

Unfortunately the Tascam is borrowed and I have to return it and find a new audio solution ASAP. Do I have to buy my own Tascam or is there a cheaper way I can get two audio lines into a Ninja 2?

If any of ya'll have any suggestions, thanks in advance guys:)

Which specific model of Tascam were you using? And what model of lav mics do you have?

Hi Jay!

I've already returned it but I believe it was a Tascam DR-40.

I have 2 sets of Sony wireless lavs (a UTX-B2 mic UHF Synthesized Transmitter and URX-P2 UHF Synthesized Diversity Tuner)

PS: I do have a Zoom H1 and I also have an XLR adaptor that I might be able to plug into the Zoom's line in.

Continuing with another DR-40 is probably your best bet if you have been satisfied with the results so far. You can get one for $167 currently from a reputable online dealer if you search around.

You could use your Zoom H1 if your adapter cable is properly wired to convert your two receivers to the stereo mini input. That wouldn't be as physically secure as what you had with the Tascam previously.
You'd have to test that out carefully, and possibly buy a new cable that's exactly correct for two mics into one jack if needed.

If you aren't also recording on the audio device, but just using it as a preamp for your Ninja 2, you could get cleaner results using a mixer with better preamps than the Tascam or the Zoom. However you wouldn't be able to purchase a good, small, new, battery-powered mixer for as low as a DR-40. Renting, or buying used might be possible, but not if you are in a hurry.
Plus, the sound might not match what you've already shot.