3D Printing Costs

so, i want to start selling 3d printed models, and I’ve got this mini darth vader model, if I were to click on the .stl file, the windows app says estimated costs £85?

the model’s around 113mm tall,

so i went onto sgd3d a 3d printing service, and it said costs were going to be £131

sculpteo said £200

went to 3dvikings it said £14

went onto treatstock, instant order average services said 15-25$

How much really is the model costs? i don’t want to use different services when buying and shipping, i’d rather have a stable price, and then be able to sell it properly

I tried a cuboid that was around 100mm tall, it said around £20 on the same sites?

can someone break it down?