So i was thinking if i send a bitcoin transaction without the miner fee or a very low fee what will happen ? would i get the coins back eventually ? or they will just stuck there forever ! and if that happened how to do that double spend ?
It's, sometime, called Double spend. the bad news for you is that minners will ignore your transactions, they won't be confirmed. The "good" news for you is that you can cheat that Bitcoin because you can tell people that you signed the transactions but it is not and will not be confirmed.
Aside from that, you will also get to have much delay in accessing your coins. This is really a sad part. It may really take time before your money is give back to you again after a failed transactions.