I just went through this! A few pointers
1. Diagnosing the problem is critical- there's a hundred different parts that could cause this so you could spend forever trying to fix it if you do trial and error
2. Cheap used parts on ebay are a good way to go- at least to prove which part you needed. You can always buy a new part later to replace the used one
3. If there's a refrigerant leak, there's not much you can do. Finding the hole is difficult and often it's in a place that can't be repaired or replaced
Do you want help diagnosing?