Just wondering if there is any other way to listen to my own voice and my guitar through the headphones other than a mixer and a microphones. I live in a small apartment and want to practise quietly. I own a electric guitar and a fender mustang mini amp(one input). Currently, I practise plugging my guitar into the amp and listening it through the headphones. Now I want to practise singing and looking for simple and cheaper method to listen to both guitar and my voice while I practise. I have no intention to record, just want to practise. I already know a mixer and a microphone can do the task, but they are expensive and complicated for me as I am a beginner.
If you want to hear your voice through the headphones, it's going to be difficult to avoid using a microphone!
You might be surprised at how cheaply you can buy a small mixer with inputs for guitar and mic. Look at the Berhinger stuff. Maybe no need to use the Fender amp at all - mixers generally have a headphone output.
My initial thought was practicing with only one headphone in so as to hear both the guitar and the vocals, but I haven't actually tried it to see if it works. On the other hand,
Do you absolutely need to have the headphones? I was thinking you might actually want to try practicing unplugged (maybe on an acoustic, depending on who you are as a musician) with no headphones at all; that will be a lot quieter, and you'll easily be able to practice singing.
Now, I don't know of any way to get the singing to be quieter in practice besides just not singing too loudly, but for the guitar playing, practicing either unplugged or acoustic will produce the same sound output as playing electric with headphones (from a neighbor's point of view, I mean) while allowing you to more easily hear your own singing voice. It also can do wonders for your guitar technique (this is contested, though; see below), since you really get to listen to your own sound without hiding anything behind distortion or the like. Be careful, though, as playing with an amp is its own skill that also needs practice; it is important to practice with an amp if you want to perform with an amp (gain can really accentuate technical flaws like poor muting technique, for example). Personally, I like practicing both ways.
Honestly, this could be another question entirely, and lots of people have their own varying opinions on this subject. But hey, if you like taking the opinions of strangers on the internet - and you do, because you're listening to me -, here's some debate on the merits and potential issues of practicing electric guitar unplugged:
A blog post warning about the potential consequences of practicing unplugged due to practicing differently than performing: https://forum.troygrady.com/t/warning-practicing-unplugged-can-be-highly-detrimental/6452
John Petrucci (he's kind of a big deal) has spoken before about his opinions supporting the idea: https://www.guitarworld.com/features/john-petruccis-top-3-practice-tips
A discussion debating playing electric unplugged: https://www.thegearpage.net/board/index.php?threads/do-you-practice-electric-guitar-unplugged-is-it-a-good-idea.1843531/
Another similar forum thread: https://www.ultimate-guitar.com/forum/showthread.php?t=1599432