John
 
Its a Talent device and can be had for $39.95 US. 

the elusive 'talent' button, and for onlyh $39.95, who'd have thought it would be so cheap? . . . i think there will be a run on this

That won't really work because it's going to mix the monitors with the vocals going to your interface. You would have needed a  mixer with Aux outputs or direct record outs.  And my guess is there's no ASIO driver so that's a big waist of time farting around with that. 
 
This is what I use for both the studio and for my live in ear monitors. There is both an XLR input and output as well as a 1/4" TRS monitor input that can be set for stereo or mono.   It does not change your mikes signal and then the monitor mix and the mike can be individually adjusted.  They are $80 in Canada. I have 2 of them , one is I think 20 years old and still works. I can have my volcals at the perfect level , I have 100% control. I can use it anywhere on any system. 
https://www.amazon.ca/dp/B00J14G7OO/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=1977604502&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B001032IDS&pf_rd_m=A3DWYIK6Y9EEQB&pf_rd_r=RC9JYB0RJAJCSKT6Z8EW
 

Just so we can all get past the price, the peso is around 20:1 which means I paid roughly $74 US. OK?
 
It's described as a USB mixer but there is no USB input. The only USB is on the back and it's for power. Assuming you could convert USB input to RCA jacks, then it would work but Mexico doesn't care much about misleading advertising. The reason there's no manual or signal flow chart is because it's not necessary, it's a Karaoke device whose function is obvious (to me now). Yes, I've figured that out. It only does this:

• Music in, voice in, a mix of both out.

The rest is just there to accept different sources for the music, the buttons direct the output to either monitor or main. The questions I had in the store (in Spanish) all seemed to be answered adequately.

• Does it mix vocals and music? Yes.
• For recording? Yes. (this is where I should have been more specific)
• Can you vary levels in the output? Yes (etc)

The dude wasn't wrong but obviously he didn't understand the desired application.  
 
I live in Mexico and it's very difficult to get stuff from the US. Most US vendors won't accept Mexican credit cards, they must think I'm laundering my $74 bucks. If you can get something shipped, Mexico wants 16% tax and another 16% import duty so you might not save any money, especially after shipping. It can all be fudged, some vendors will even change the amount on the receipt to help you out but unless you have a friend coming down to visit, it's can be a lengthy fiasco. 
 
I may be able to trade up at the same store or get half back from a DJ type person.

The only USB is on the back and it's for power.

 
It more than likely uses USB for power & audio since there's no power jack. I cannot say it's false or not but the manual & video both say the USB is 2 way audio in & out to your computer. If so It should work like any USB interface with the right drivers.
 
Quote from manual:
connector.
 
http://www.parts-express.com/talent-mix-r-mini-portable-3-channel-mixer-with-usb-audio-interface--233-120

Looks like a behringer unit.

My Nephew lives in Pueblo. They run a church and an orphanag there. He got into sound in a big way because of the issues as you say with just getting gear good gear. Because he also is 100% bilingual he got a job writing technical manuals in Spanish for Meyer sound and a few other high end audio companies.  
Our family knows all abut the things you just can't get down there. Our suitcases are always packed with special orders from Canada. 
 
If you can, trade it for any small mixer that has an auxiliary send. That would allow the vocals to be sent from the mixer to the interface without the playback being heard too. I have a Mackie Mix 8 that would be perfect. I'm sure they sell those down there somewhere. See the green knobs and then the Aux send goes to the interface line input