Doesn't matter huge amounts or small. You simply stick to the biggest and most important tule of all. Never invest what you can't afford to lose.
In other words. Money you CAN afford to lose, that's what you put into investments like these. If you need the money later or some other time, don't use it.
Doesn't matter $1 or $100. Just apply the rule.
Altcoins are just so, so risky.