Ok, so here's what you do.
Step 1) You take out a sketchpad. You come up with concept art for an outfit/costume you can wear to parties. This costume is not something based on other influences. It's not something that's kind of like something else. It's not something that you'd say "Oh, this would belong on this tv show, or movie". It's completely unique. It stands out. It has a presence all in it's own. You wear it, and it looks good on you, and people remember the outfit. If Spiderman were real, and he just showed up to a party, you'd be like "Whoa, look at THAT guy!". Your costume doesn't need a mask, and in fact would probably be way better without a mask. Just a guy/girl at a party, doing their thing, and completely stealing the show just by being there. That's step 1. Buckle up, because it only gets crazier from here.
Step B) Hire about 10 people to walk everywhere with you. Like an entourage. Have them basically simp you in public. Except the idea is that nobody knows they're paid actors. From the general publics point of view, you're just some guy at a party, and these people love you for some undefined reason.
Step ∆) Now you release T-Shirts of you. And your simps all have the released T-Shirt on. And now you also hire another 10-100 actors. These ones will NOT hang around you as if they're in your circle. These new actors just spread out amongst the party. And they too are also wearing your new T-Shirt. So now there's 10 people all wearing the same shirt, all following you around, and another 10-100 people all single, and drifting about the party, all wearing that shirt. So now it looks like your inner circle love you, but so do the general public. And these shirts can be purchased for $80 each.
Now do this same set of steps every weekend, at every party, and really fuck with peoples perception of what the fuck is going on? All these people bought an $80 T-shirt for some guy? What is happening right now, and also, who IS that guy? You could also adopt a stupid show name, like Princess StinkyPooButt. Even though you're a 6'1 250lb guy with a beard and no legs.
And now the question becomes: "Will idiots buy an $80 T-shirt of absolutely nothing?"
As I look around the world today, I see a lot of idiots. I like my chances that I'm going to sell some stupidly overpriced T-Shirts of bullshit.
Api costs are pretty crazy, its much cheaper to just use the platform that comes with the broker, but most of them have indicators and the ability to make custom indicators and rules. Plus, you aren't out of the woods yet because in addition to the API fees you usually need a real time data feed provider for the instruments you want to trade. This basically narrows your options to a few reputable brokers that have platforms that let you access data for relatively low cost but give some automation options.
The other thing to keep in mind is the pattern day trade rule if you have less then 25k. You can get around this rule by not buying or selling the same day, but it limits severely the number of trades you can do in any given week. As far as using your bot, TD Ameritrade has their own indicator language and you can make the indicator into a bot. IKBR has alerts that you can turn into an automatic buy or sell order without using their API. I would stay away from Robin Hood, they are good marketers but I don't like their platform.
Out of all these options, IKBR and TD Ameritrade both have small accounts you can get that have free commissions if you don't do a lot of transactions, and IKBR waives the data fees as well for smaller accounts right now, probably due to Schwab just buying out TD Ameritrade and trying to stay competitive. If you want to not do stocks or options but only want to do Futures or Forex, NinjaTrader has a pretty robust programming environment based on the C language called NinjaScript, but you will be stuck paying at least 20 bucks a month in data feed costs even if you go with their brokerage, but they do have a fantastic platform that has many automations and options in itself. Forex, not sure which brokers are good, you are really entering the wild west there.