Start with whatever you can afford, decide on an investment strategy and stick with it. Don't let emotions cloud your judgement.
My strategy is to use GDAX, the trading platform, to buy ETH for example, and then trade in bite size pieces. Take small profits on several trades and keep reinvesting. This way, you can make a profit regardless of where the market is sitting. At the same time you are making small profitable trades, keep some long trades, then when the market spikes, you'll win on them too. Cash out for a nice profit and then reinvest when the market is low again.
If you don't have capital to get started, you can scrap togther bits of crypto from faucets and mining games. Follow the same procedure as I mentioned and you'll still profit. As you make larger profits, keep reinvesting. I put together a free report on my website that outlines my faucet project, if you're interested in investing your time to claim some crypto. The report is at
http://terrytelford.com/free-bitcoinThis may not make you the richest man in your country, but it can give you a headstart