The market opens opportunity for investors and I want to take the opportunity to somehow start my investment.
Have you thought what kind of investment will that be? When would you like to withdraw your profits?
What should I buy?
Whatever you buy, you'll have to understand if you're going long-term or short-term. If you invest $250 on almost every cryptocurrency with potential and “bright future” right now, you'll see profits long-termly. The short-term way is dangerous, as always.
As for the title's question, I'd put them on Bitcoin. The other one is far more centralized and less secure. Not to mention that I don't agree with the way it works.
any advice?
Do not invest blindly. Understand each crypto's ability and judge by yourself if you think that it'll be useful in the future.