Well, the price of a coin depends completely on it's Market Cap, and it's Circulating Supply. Divide one by the other and you get the fair market value. The top 100 coins have the largest market caps, and generally trading volume. If you want to invest, then just pick several of the best cryptocurrencies, buy some, throw them on a Trezor, and forget about it.
If you want to make money trading, then you need to learn charting, or just join a group. Trading groups vary, but most offer free signals, and then VIP paid signals. If you don't have experience trading, then you're probably going to lose money. In my experience, it's worth the $50-$100 bucks a month to get signals sent to your e-mail, phone, chat room, etc. Then you just plug the numbers in and make money. I'm a good trader on my own, but even I pay for multiple signal services, and off their calls I earn back multiples of what I pay out.
You get what you pay for. If you're interested in trading, I recommend the guys over at Cracking Crypto. They're the most knowledgeable group I've met, and it's a pleasure to work with them. They offer free services, but also a paid service if you're looking to take your trading to the next level.
You can join their Discord right now for free, they're holding it open to new members for one more month. Tell 'em Disputin sent you.
https://discord.gg/EmmBNEY