To get good prices for your 3D printing parts, you need to find the right service provider for each request. A benchmark from ETH Zurich1 shows price differences of up to 96% for the same part in the same material built by the same technology.
But, depending on the order, different providers are price competitive. At quantity 1, provider A is cheaper, at 100 provider B.
Therefore, for each part several quotations should be compared.
1 E.g. Baldinger, M.; Duchi, A.: Price benchmark of laser sintering service providers. In: High Value Manufacturing - Advance research in virtual and rapid prototyping. 2013. p. 37-42