I was hoping that someone who had the eyelid procedure done would respond to your post because they would know better than I do on what the approximate range of cost would be. My understanding is there is quite a large range depending upon whether you have it done in the specialist's office under local anesthesia or whether you have it done in a facility under general anesthesia. There appears to be a difference in cost between gold or platinum weights. And different specialists seem to charge different amounts for the same procedure.
So, even if someone posted how much their procedure cost, that doesn't mean yours would cost the same amount. Another issue is that most insurance plans in the U.S. cover the procedure, so if someone here did post how much theirs cost, that amount would be different if you had a different insurance company or, as you said, you didn't have any.
My recommendation, for what it is worth, is to find what specialist you think would be a good one for your needs and then give their office a call and tell them your situation and ask them what the probable cost to you would be. Don't ask the doctor because they generally do not have a clue for patient costs, but ask someone in the billing department as they deal with the costs associated with the procedure and should know what an uninsured person may pay.
I certainly can understand why you would want to replace your gold weight with a platinum one. I wish you all the best in your search!