Next time he tells you to wear the bracelet, tell him if he likes it so much he should wear it
Say that it doesn't go with your outfit, you need a white gold one but as you don't have one you the best one to go with it is [any other bracelet you have that he didn't give you].
And actively tell him that he is not being helpful in finding you cheap alternatives, he is actually being unhelpful. And if he tells you that you are being silly, point out that no, he is being the silly one - don't let him win the argument otherwise he will always think he is in the right.
Does he ever want particular things for his birthday/christmas that you could start doing the same thing back to him that he does to you? YOu mentioned the different cars but I am guessing you probably don't give each other cars as presents...
So for example, if he supports a big footie team, could you give him the scarf for their enemy team the local Division 99 team 'as it's still a football scarf and you found it much cheaper than the other team's one, it's a football scarf just the same'. Or if he has a regular brand of beer/wine/baked beans that he really likes, stop buying it and start buying the tesco extra cheap basic value range version of it instead. Anything so he can see that the value something has isn't just about the cost in pounds, but about the context, the taste, the design, the quality, the ingredients etc used to create it...
It has to be something he really cares about though otherwise it won't work...
Good luck. And if the worst happens and he does buy you a watch you don't like practise your best disappointed face and in your head know exactly what you are going to say so that he knows you are upset that he has gone ahead and bought you something you had told him you didn't want, that it is not about the money spent but about the control and ignoring your wishes, and that please can you have the receipt so you can take it back and get something you would like he might as well keep it as he obviously likes it as when he bought it he knew you didn't like it let alone want it.