about $90-$150 initially, but usually within a few weeks the balance will be upped to $400 or so.
I have had troubles with people using the service as a way to get money off stolen credit cards, so the low initial deposit is a way to avoid that.
There is also a lot of per-customer randomness to prevent bad guys writing logic to detect which wallets are provided by my services. That's why they don't all have a fixed balance.
> Seems like you could achieve the same result if you just let your customers buy their own coins and provide an address for you to watch?
Yes - there are other services that do that for free already. This is more of an all-in-one setup for those who want to set-and-forget.
If this is a Node.js program you should store private variables in a .env file (with .env added to your .gitignore) then call process.env.[variable name here] to get the key at runtime.
Look up documentation and examples on .env files.
If you deploy to a service such as Vercel or AWS you can set environment variables there for production.
When I used to work in Crypto we had git hooks set up to prevent this from happening. It takes a bit more time to set up than just adding something to .gitignore but is a more robust solution of you design your hook well.