there really isn't any kind of limit to how much you can profit from investing in altcoins. it can be from losing 100% of your investment and going down to 0 up to millions of dollars!

it depends on a bunch of things. starting with your experience in trading and in knowing how altcoin market works conversely the pump and dumps. if you have no experience and want to randomly buy based on what others tell you and what they hype up then you will end up losing a lot of money.
then it also depends on how much you are willing to invest and take risks. obviously you can't become a millionaire investing $1 but you will be taking a much bigger risk investing a higher amount.