I don't know much about the market of video games. But, I thought maybe my two cents may help anyway (or, they may not, feel free to discard my inane ramblings).
Basic Economics teaches that "you charge what you can get away with". That means... you don't really charge what you think it's worth. You charge what the consumer thinks it is worth. That is to say, do you think you will honestly get $20 for it? $15? $5?
From a consumer standpoint... I rarely buy a video game. Why? Because even if they're AAA games... they're all pretty "substandard". Or rather... not what I'm looking for in a game. I don't buy RPG Maker Titles for the same reason. Oh, I put them on my Wishlist and say to myself, "I'll buy this at some point, just to give it a chance" and then really don't buy it. Even though I use RPG Maker, I have no illusions about the amount of Drek that comes out of the program and is sold on Steam. If I know that, despite being a fan of the program, and wanting to produce my own games with it... it's a safe bet everyone else knows it as well.
That being said...
If it's your first game, I really wouldn't charge anything more than $5. I wouldn't expect to make a profit at all on it. Or have it sell well even at $1. You're an "unknown". Unless you've created the next "Last of Us" or "Portal" or whatever equally ground-breaking game you want... You're going to probably do little more than sell to random people who happen upon your game and go, "Eh, might be worth $5" and pick it up on a whim.
Personally, I plan to give away my first game. All four "chapters" of it. Because, frankly, I know it won't sell, it'll largely be complete crap and need several revisions, reworks, bug smashes, and fixes that players will find... that I won't. My first game is going to be garbage. I know this. Despite all the "high concept" stuff I put into the game, I am under no illusion that it will be executed perfectly... much less "well". As such, I expect to use that first game that is free to... Build up a potential customer base. To build good will. I know that even if I charged money for it, I'd not make a profit on it at all. That's fine. My first game is to get my name out there. If my first game and its 4 chapters attain a minor fan following (I'd consider 100 people good enough), then I might consider charging $5 for the next game I make. Sort of a, "Hey, if you liked this game I did, you may like this one too! But, it costs $5, so you gotta pay a little for it!". I might do a dozen or so games at that $5 price tag. Build up a consumer-base. Maybe later games, I charge $10 for. I'll probably never get to a point where I feel comfortable charging anything more than $20 though. Not on RPG Maker. Maybe if I were working with Unity and doing a lot of programming and stuff and pushing graphics, the engine, gameplay, other stuff... I would. But, it's RPG Maker.
But, I'm not a guy who plans to turn game design into a career. For me, it's a hobby. A hobby I engage in because I want to share my stories with people. Nothing more, nothing less. It's something I do in my off-hours. I'll get to some point where I probably turn it into a company and such, for tax reasons and such (since I'd have to declare any money I made as taxes, and they'd ask me for a business license once that happens, which means I should be a freakin' company before selling it, otherwise I might get nailed by the IRS for undeclared income...). But, as long as I charged zero for my games... No need to pay taxes on a company, or start one, or get a business license, or worry about paying taxes on Income...
Yeah, without a decent promise of income, I plan on charging $0 for my games. If there's a point I think I can "break even" after all the nonsense of getting Legal with the Government... I'll charge money then.