As for the search, now you can find all the valid patents of China Patent Office directly from the Internet without spending that money. There are not enough foreign patents.
There is a small risk to bear, that is, the patent office only publishes patents that have already taken effect, and it usually takes one to four years from application to approval. Once the approval takes effect, it will be protected from the date of application. So you can't find these patents from application to approval. In other words, it is possible that someone applied for a patent before you, but this application was not approved, so you can't find it. Once approved, your application is after his application, and he can ask your patent to be invalid. If you implement it, it also constitutes infringement.