How to get started cheaply?

I'm gonna go the opposite way a little bit and say that I recommend finding a solid hot-swappable keyboard that has what you're interested in.

I found a reskin of the Rak Lam-Ang Pro called the Falcon Elite TKL on Flashquark - it's about $80 for the board, USB-C, Bluetooth with profiles, USB-2 for a dongle or extra port and the whole reason I got the board, a media scroll wheel. That's what I wanted most and so everything else was just how to make it feel.

To research switches you can think about what you like for typing - do you want some resistance, some resistance from a click, a little or a lot, and how do you want the sound - do you want it quiet, clicky but quiet, or clonky and loud?

Any combination of those is just from the material of the keycap and the style/type of switch and how they sound together when the switch clicks and the keycap touches the board.

You can usually get a switch tester for $7-20 or so, I opted not to in favor of just looking online with an idea of what I had in mind. I actually needed 2 keyboards for 2 different PC's, but I used the same board for both. I wanted one to be as quiet as it could be so I got the Kailh Pro Purple Switches which are OK but serve the purposes for a music production PC with minimal typing. They're smooth and quiet. I'm also just using standard ABS keycaps on these, for a total of $35 for 88 switches and $20 for the keycaps for a total of $135 for a starting keeb. That rivals a lot of prebuilts and you get to upgrade it on your own terms.

Like I said though, those switches are only OK and for gaming I wanted something better. I went for Kailh Speed Switches - Copper ($8 for 35) and Outemu Phoenix Switches (50 for $35 when I got them - priciest so far). These two are tactile switches which mean they have a small bump that makes a click and these ones have a shorter travel distance, both unlike the Kailh Pro Purples.

These two were much better for that responsive clickiness than the Pro Purples, are clicky but not too loud and make it easy to feel exactly when you get the button pressed, for just $43 for 88 switches - not much more than the others for a better experience. There are just better smooth switches than the Kailh Pro Purples, that's all.

For the keycaps on the Phoenix/Speed Coppers I got PBT caps which just feel a little firmer/stiffer/less flex and are textured. If you're a drummer, ABS on plastic sounds like a high tom and PBT on plastic sounds like a low tom.

There are also keyboard mods, alternative stabilizers, o-rings, tape/foam mods which aren't too expensive ways to add to your experience. I replaced my stabilizers for the shift/enter/space keys (2u and 4u) because the ones that come with are decent but nothing special.

Finally - the last reason I recommend this kind of option is repairability and warranty. Some can be trusted, some can't, why take the risk? A hot swappable keyboard lets you accidentally spill your water/beer/soda all over your keyboard you can turn it off, remove everything and hose the sucker off and give it an ISO bath. A slightly wonky media scroll wheel is the only byproduct of the event... Oh and I think one switch got ruined. I've had keyboards die because I couldn't properly clean it so for me being able to get right to the PCB can do a lot for some headaches.

But anyway, I hope this gives you some insights! $135-150 for a first keyboard isn't exactly cheap but it's not entirely expensive either, especially given that you get to swap out. If you really don't like switches you got I think the resellers market is decent? If you're looking for $40 ones then my apologies, but if you're looking for mid-range ones then this hopefully is helpful! Oh - also I'm not actually recommending the Falcon Elite TKL or the Rak Lam-Ang Pro - I'm not sure if they're even currently available or not. They're decent keyboards but it's just plastic and PCB and it's not exactly... lets say designed with sleek fashion in mind? It's just a cheap solid keeb that has features I like. For $80 I'm sure someone can recommend a better base board with the same stuff! I just happened to like this one so I got two and that's my mech-board experience. Is it endgame? No, not really. But I've had these for as long as I've built my PC's, so that's pretty close eh? Haha!