This is my opinion: As it turns out, budget agents don't save you money. They are often slow and complicated.
Too many times I couldn't order on a budget agent's website because the Taobao or Weidian API service was not working.
Some of them make paying insecure and complicated by having you pay through family and friends and requiring photo id.
The risk of total loss because they don't send your parcel to the correct address is real with budget agent's and it happens way too often.
Budget agents are also known to fill out customs forms incorrectly, resulting in higher payments and complications.