So I was in the market pre june 2019 when all hell went loose and If you actually want to be made in the game you're gonna have to spend a lot of the money on accounts, proxies, and more accounts when they inevitably get banned. The goal here for most of these no refill services is to put followers onto your account for that period which they claim(almost never happens) so that when the accounts get banned, they make enough ROI that they can buy more accounts and rinse, repeat. Maintaining a "refill" service usually just means finding really cheap followers that you can add again to "fill" it up and then just doing that until the refill 30 day period is done or something.
Now let's assume you drop a minimum of $1k on accounts and proxies. Now you gotta find your social media API key or get a bot to do it which is a whole other story.It is not just about getting a bot one time and then you are good. SM companies pay a lot to circumvent these bots and WHEN not IF they change your bot you need pretty much a full-time programmer to have your service working again instantly so your service doesn't get a bad reputation or taken off the reselling panels.
If I recommend someone get into producing likes,follows ect, make another service that not a lot of people are selling, find a way to do it cheaper and do it but I think that if you are not already making IG bots 2 years ago then it is really hard to establish yourself to these panels.