Most altcoin prices, maybe except for the Top 5, are usually measured relative to BTC. You will then see a price of 1100s for TRX-BTC as an example. While it's easier to see $0.20 at first, the relation to BTC will make sense after a while.
While investing, you should always have a reference. Investing in regular stocks is done vs $, € or other currencies - but a comparison to the most common index, S&P500, NASDAQ, DAX would make more sense. If your stock goes from $100 to $110 you will make a profit but if the index goes from 1000 to 1200 in the meantime, you are below the market.

Unless BTC becomes super stable, you should measure your profits against BTC (or ETH for some pairs/exchanges). A few weeks back I made 25% with NEO from $20 to $25 but BTC went up 30%+ in the same timespan. The NEO-BTC went down so I should have stayed in BTC.

This works best during BTC stable or growth phases. During crashes like the one around Christmas, both BTC and altcoins will lose fiat value so you should convert everything to fiat/USDT to buy back in cheaper or just hold through the crash.