Unfortunately, the only option you have is to quit. Since you don't have an employment contract
with the dealership, then you don't have any contractual guarantees that deals will be given to you or your co-employees on an even basis. Further, Texas law does not have any protections that grant you an equal right to deals in this sort of arrangement.
That being said, there is another tactic you could attempt. You could arrange for a strike. If you can get all the other salesmen to agree, then all of you threaten to walk off the job unless the boss agrees to start spreading out the deals in an even and fair fashion. The fact that all the salesmen would walk off the job at the same time would put much more pressure on the boss to be fair then you simply quitting.
That being said, unfortunately there is no legal remedy which can be applied to your case to help you. Let me know if you have any other questions or whether there is more information I can provide you with.
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