How can bitcoin coins have real values? I had this question for some time and i couldn't have a clear answer.

How can a new entity (coin) have a real value, in USD for example, and be able to trade with it when it has no real life equivalent like Gold.

anybody has an answer ?
First of all, "real value" is a questionable term. Some people deny a concept called Intrinsic Theory of Value. Anyway I can give us some reasons:

1) Limited supply and increasing demand

Bitcoin (as some other cryptocurrencies) has a fixed supply, which is currently 16,8 millions of units but it is going finish in the next years, when it hits 21 millions of units. 

This supply of units is totally public through its ledger, which brings us an authentic and transparent scarcity.

According the classic economic model of Supply and Demand, if the demand increases and the supply does not increase in the same speed, the price will increase.

2) Bitcoin is a more effficient payment system

You can send an amount of money for an relatively small fee in a short time. The current systems simply can't send 3000 USD from NY to Japan in 10 minutes for 2 USD less than 1 USD and the next updates can make it cheaper and faster. 

3) High liquidity and media coverage

Anyone can trade relatively small amounts of bitcoin in Internet. It doesn't have the same limitations or restrictions that other markets have, like trades with minimal amounts. It has more liquidity than stock market, as you can trade in smaller positions. 

So, if the Bitcoin market is bullish it trends to be really bullish, specially when media coverage show how bullish it is and much high it is performing, which brings more interested people to the market - even people who doesn't know exactly how Bitcoin works, how its blockchain works, etc. It happened specially during 2017. So we have an explosive scenario, where:


Bitcoin price increase much more than other investments in the same
timeframe 
Media coverage about Bitcoin performance increases people
curiosity 
Bitcoin is easy to trade in relative small amounts and
people buy some Bitcoin
Repeat.