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 ?
Bitcoins never go into space. You will either get the transaction returned or it will be included in a block.
But safer to include at least the minimum fee, so it would only be a matter of time and the transaction would be confirmed. Miners are actually business people and they are rendering some vital services, so they deserve to make some profit, only their charges are now becoming outrageous and people are beginning to complain.
Mining bitcoin is a serious business and when we say a serious business, it means that it needs a big capital to start the business and maintaining the business. That is why it is just proper to compensate miners well because without them, integrity of bitcoin transactions would be at stake.