Is there any way i can play minecraft (bedrock edition) for free in ubuntu?

Tl;dr: No, you can't.

Here's the real answer:

You have two issues:

  1. Minecraft Java Edition can be downloaded for Linux. After you pay for the game, of course. Minecraft Bedrock Edition (a.k.a. Minecraft: Windows 10 Edition) won't work on Ubuntu (or any other Linux distro, for that matter). It is distributed via the Microsoft/Xbox store. Not a downloadable .exe. So you can't download that version for Ubuntu. Some people (Reddit link) have gotten it working on Linux. Here is another one. So it is technically possible, just hard.
  2. It isn't free. Neither Minecraft: Java Edition nor Minecraft: Bedrock Edition are free (on Windows, Mac, or Linux). So you have to pay.

If you want an easy way, I'd just create a Windows 10 VM using VirtualBox, or just play Minecraft: Java Edition.