I currently have a very simple setup for recording vocals on top of pre recorded backing tracks using the Blue Yeti USB Microphone. The mic provides a headphone jack which lets me play the backing track through my headphones while simultaneously providing a low-latency monitor for my voice, so I can hear both myself and the backing track through my headphones while I'm recording. The output from the mic to my PC only contains the input from the mic, not the backing track that I hear through my headphones, which lets me apply effects to my voice in post without affecting the backing track.
This has worked great for me so far, but lately I've been thinking of upgrading my setup to support additional mics and possibly instruments. Recently I also started experiencing some technical issues with the Yeti Mic (it randomly disconnects from my PC), so I think perhaps now's a good time to upgrade.
Now here's my issue: I want to build a setup with support for multiple audio sources which retains my current setup's ability to monitor both the backing track and mic input (with low latency) through my headphones while only recording the mic input with my PC (not the pre recorded backing tracks). I'd also like to keep the setup as flexible as possible, so if I want to do further upgrades in the future I don't have to replace too much of my existing hardware. I'm also on a rather tight budget; I'd really like to stay under $200, assuming that's realistic given my requirements (so far my research seems to indicate it is). What sort of hardware might I need for this setup?
One option I'm considering is a dedicated audio interface like the Scarlett 2i2. This definitely has the capabilities I want, but it's rather expensive compared to other options I've explored (see below) and doesn't offer as much flexibility for further upgrades in the future.
The other option I'm exploring is the idea of purchasing a mixer board like the Behringer Xenyx 802 and pairing it with a cheaper audio interface like the Behringer UCA202 (or maybe using a board with a built-in interface like the Behringer Q802USB). The boards I've seen are actually cheaper than the Scarlett 2i2 and offer more channels, but I'm unsure whether they will allow me to simultaneously listen to the backing track and main mix through my headphones without mixing the backing track into the main mix. After reading the manual for the 802 it looks like there is a button that lets you monitor the 2-track input without sending it to the main mix, but I'm unsure if pressing this button would play only the 2-track input through the headphones (not what I want) or play both that signal and the main mix through the headphones (so I can still hear my voice in addition to the backing track).
Will the 802 or another, similarly priced board do what I want? Should I just give up and go with the Scarlett 2i2? Is there perhaps some other option I haven't considered yet? Maybe a really cheap, dedicated piece of hardware for mixing the backing track into my headphone output? I did look at a couple mini mixers, but they all seemed to only handle mono audio sources (not great for stereo headphones), and the ones that did support stereo were almost as expensive as some of the full-sized mixing boards I looked at.