One of the main reasons Sand Goblins can play a good economic game is the Sand Scavenger, a highly efficient unit. If the Sand Scavenger kills a unit, you have virtually played a 0 cost 3/2 that, if not killed immediately, can easily retrieve another card thanks to its 3 strength.
You can try to protect them with a unit that has a Thruster Upgrade that covers it after it kills something, but this is not really needed for them to do their job, it is okay to just throw these guys carelessly to a target that they can reliably kill.