Unless it's corroded, a new carburetor is likely not needed. For a proper cleaning you have to take it apart. Use the little tube to shoot cleaner and compressed air through every hole, especially the small ones (wear googles). Putting the disassembled carb in a hot ultrasonic cleaner for a while is well worth the effort, then repeat the spray cleaner and compressed air afterward while it's still hot. The problems will be hiding in the tiny holes and tiny tubes that you can't see easily, that's where you should focus. In my personal experience, the knock off aftermarket carburetors are not as good as OEM, the engine will likely run but not as good. I've not personally seen the seafoam treatment make any significant difference on a truly dirty carburetor. You have to disassemble it and get in there.