I think paintball is like many other sports, like golf. You can do it expensive and you can do it cheaply
There is a setup cost to have acceptable equipment. Which can be reduced by looking at 2nd hand and maybe not the premium or most popular options
Then you have running costs... one way to reduce this is to play pump at walkons. That will drop your paint consumption and make it a very cheap day (in relative terms)
The "problem" for most paintballers is that they are inherently keen to tinker or upgrade, resist the temptation and you can do it cheaply. Get in the habit of buying the latest and greatest, running multiple setups and not bothering how much you shoot = a big bill
What does make me chuckle is that it's fine attempting to negotiate a price... but most sellers are not desperate to sell, but some of the lowballs can be astonishing. One of the reasons I have never sold a single item (but bought loads!
)