Too Long; Didn't Read version: I've begun as a GM, seem to be doing ok, and want to progress into becoming a Paid GM properly. What would you expect from me?

I'm a GM and I've been a GM of other games such as Mutants and Masterminds and Heroes Unlimited; I'm new to D&D and only started running games in the past... what... 2 months?
I started running games because I couldn't 'fit' into other groups as a player or couldn't find a slot (any available games kept filling up faster than I could apply). It does seem that I'm able to run a game as a GM much better than I can play for some reason - I've not quite figured out why that is, I know it probably doesn't make sense, but there it is.

I have four groups going, all sharing the same world, so lots to do! - AND the way I've run things so far seems fun and successful. I think that maybe... just maybe... I have what it takes to GM. Maybe.
The downside is that I've got just enough money to pay for life and a subscription for Inkarnate. I chose that one because I love making maps and for $25 a year, it seemed reasonable. 

I don't own ANY of the sourcebooks or adventure books. What I do have, however, are some very nice players in my groups who have shared content with the campaign. This is a GREAT boon for me, as I can sit and read chapters at a time while also being able to look stuff up, on the fly, when weird stuff comes across the table and, in conversation with the players, work out the correct answer quickly. 

So now I want to know how I can earn money for the sourcebook pack (legendary?) and money for the premium subscription. It's nice having a couple of players sharing content but if I'm going to look at this seriously, and I want to, I would love to have the privilege of earning the books and tools myself. It just feels better to have if myself and to be able to cater to others, somehow. 

I want to look into hosting Paid games. Properly. so that I can afford the books and materials properly myself. Why? Because it would be a nice thing to have and I want to have nice things so that I can do nice things for other people.

So, the old fashioned way I seem to remember is to open a small shop with two rooms. A shop at the front selling books and dice, a room at the back with a big table and cafeteria implements such as a kettle and a fridge at the very least, disabled toilet access and the more modern invention of proper internet access, product ordering and credit card facilities. 
I calculated that, with distributor fees and brand inspection fees, new stock, new furniture, signage, utilities and insurance and taxes and rent to pay for... I'd need £100,000 for the first year alone. Not going to happen. I'm broke. :)

I noticed people advertising Paid DnD sessions. I looked into this. To run D&D properly to earn money with it, WotC (Wizards of the Coast) want to inspect the premises and such for real-world gaming before they grant their blessing, and I'd need to link up with a distributor if I want to sell the books. It's a bit of a hassle but one I don't mind doing. But with internet use, the way I'm doing it now with Discord and various services, I don't think there's any such requirement (I doubt WotC want to sniff around my Discord server, but I wouldn't mind if they did I guess?). 

But I also noticed a bit of a reputation thing floating around. If I charged money for my sessions, I feel I'd be laughed at right now and refunds demanded because, well, I'm still making mistakes and I'm not as slick as I would expect a paid GM to be. So, I'm going to keep my head down for 2 years while I keep the ambition burning in the back of my head, soak up DnD experience and try to get to know things instinctively, 

So... I'm going to keep my head down, keep plugging away at it, keep 'trying' to be a good GM while listening and learning character designs and player behaviours as and when they crop up... but I do seem to be enjoying it. 

While all that is said... what do you lot think? What would you advise to someone who's looking to turn this entertainment into a job while starting from nothing?
Also, what fees would you expect a GM to charge? I've seen prices range from £5 per session to £20 per hour! More, somewhere, but that must be crazy, right?
What would you expect for your money and at what level of payment? 

I'm not sure paid dm-ing is really that common. I know some people do it, but for the most part I think demand for it is really really niche. 

Paid DMing is also very much a "don't quit your day job" thing.  Very few people make a living out of playing any TTRPG.  Those who do are also tied up with actual TTRPG writing/design and/or social media influencing/streaming, frequently both.  

Also, I think somewhere in your lead you sort of present the idea that you may now be "good enough" to maybe, just maybe try paid DMing.  Paid DMs are not inherently any better than regular DMs, they've just worked out a way to monetize it in a way that brings players back consistently enough to keep paying for it that it justifies the DM to keep doing it.  There are plenty of amazing DMs and GMs out there who don't do it for money because they don't want a business set up to get in the way of their fun.

There's really not a lot of discussion of paid gaming on this board, most often the discussions tend to get assailed by strongly worded lectures on how paid DMing is anathema to the ttrpg hobby.  What I'm saying is, if you want real advice on best practices, you probably want to check out a forum where you have a critical mass of paid DMs in discussion.  That's not here.  You might want to try out Start Playing Games, and see if they have a forum or sometihng.

I've never been paid to run D&D; but I've run other games for $.  The opportunity was a result of basically being in the right place at the right time, having some unique aspects I could bring to my game.  Sure it was fun.  But did pay enough to make it something I'd regularly pursue as a gig?  Compared to what I do now, no.  It's almost a work to live / live to work dichotomy.  No offense, but I just got a vibe that you may be seeing a gravy train where it's more like ... well, it's not a gravy train.

I would have to say, if you are really trying to make money running games, 1.) pay attention to the first thing I wrote in this post and 2.) You need to be more upfront that your interested in selling your skills.  A subject heading "starting from nothing" on a board like this would most often lead a reader to assume you're trying to break into the hobby of playing D&D with no background or material.  Paid DM's gotta have a strong active voice.