1000 dollars is a big money for many people, and you need to know that investing in bitcoins has more chances to be profitable then in alts. You can buy/sell, to say trade, with any coin, but bitcoin still has the biggest chances to bounce back after every drop, and that is more then 2-3% profit.
Investing in btc or eth is not one time deal, you can invest even less money, but at least you will have some btc or eth. That`s a good thing about investing in crypto generally, you can invest any amount of money and you can hold that amount or to try to trade, it can be low as 10 dollars or high as 100k dollars, there are no limitations.
If 1K is big money for the OP, he probably shouldn't be investing in crypto at all, to be honest. But if it's a decent amount to him, btc would be the safest bet.
Otherwise, I like the idea the other poster mentioned, just use it for trading. Which means playing the swings right ... kind of a risk, but if he figures out how to trade, probably the way to make some money. He could just trade in BTC if trading alts seems too risky to him.
Bitcoin is the safest bet for all of us, not just him. I don`t know about OP, I said that 1000 dollars is a big amount for many people, maybe he is one of them, maybe not. I have much more money in crypto than in real, for example my monthly paycheck is around 350 euros, it`s around 380 dollars, I need to work more then 2 months for 1000 dollars.
If you are new investor it`s better to invest in some potential coin and hold. Trading is risky even for people who trade for years. I wouldn`t recommend trading to someone who is new in crypto.