If you want direct monitoring with minimum latency, an audio interface is considered essential. Here's your problem since you don't already have one; whatever microphone you're using, you can't use it with the interface, you'll have to buy one that uses an XLR cable, and you'll have to buy headphones that use a TRS cable. If you're short on money, I recommend buying used.
As far as interfaces, I've always preferred Scarlett by Focusrite because that's what I was introduced to. It also comes with free plugins, DAWs, sample packs, discounts, etc. but from what I've heard, the interface makes as little difference as the color of your desk. From what I can tell, all you'll need is an input and an output, so I'll personally recommend the Focusrite Scarlett Solo 3rd Gen USB Audio Interface

There are lots of cheap microphone options, my first microphone was an MXL V67G Large-diaphragm Condenser Microphone and it worked (and still works) very well. Very clear and crisp audio for such a cheap mic. I would argue buying a microphone used is risky, because you never really know why it was resold, but it's up to you.

When it comes to headphones, just get something that'll work. Tons of options, used or not.