There are so many uncertain elements that nobody can give you the exact estimation. The biggest cost driver is the part size. If the part is big, then the mold should also be big, the the mold cost is higher.
Plastic injection mold and molding industry is not known by many people, especially who is not in this industry. It is not easy to understand and very professional. But you know, it is widely used for many products and many industries.Almost all of plastic products or parts should be made by molding, just different processing as per the different design. Such as: injection, blow molding,rotational,extruding,rotocasting,etc.Of course, the most widely used is injection molding.But as a green hand in this industry, when you come up with new projects which requires plastic injection molding, what should you do? As a sales in this industry for more than 6 years, Below are some guidelines for you:
1.About the design or samples or prototypes.
If you need a quote, the manufacturer must ask whether you have 3D drawings or ready or samples available? Without a 3d drawing or sample or prototype, the manufacturer won't give quote to you, not because they have a bad attitude, but because even they give you a quote, it should not be precised, and they can not go to the next. It also shows you are not actually working seriously on it. So when you want a quote, the first step is to have the design or sample or prototype on hand. For the 3D, to save cost, you may pay a university student in engineering major, even he/she may make some mistakes that the design is not tool-ready. But no problem, the manufacturer can tell you where is wrong, and can give you a quote based on tool-ready solution. If you place the order to them finally, they can modify the design to be tool-ready for free. If you just want to copy or make a similar part from existing market, you can buy a sample and send it to the manufacturer, let them know where you want to change, and then the manufacturer can quote. If it is a new part or product, if you can have the prototype made, you can also send the prototype to the manufacturer to quote.
2.About the quote elements:
1) cavities: this is the most basic element for a mold quote. If the part is not very big, usually the manufacturer will ask you how many cavities you want for the mold? If you want 2 cavities, that means you can get 2 pieces from the mold one time. The more cavities, the bigger the mold should be, and of course the mold cost is the more expensive.But on the opposite, the more cavities the mold, the more pieces you can get per shot(=one time), that means the production speed is higher, the per piece cost for production is less. Oh my, too complicated, I'm stupid about it, what should I do? No worries, I can tell you an easy solution: You can just tell the manufacturer how many pcs of the product you need per year and in the future. Then the manufacturer can calculate how many cavities is the best to save cost for you, and provide the quotation to you.
2) mold material
Mold material is also a big price driver. A mold price can vary from 2000-10000USD if you tell no background to the manufacturer. Of course, we know mold material are usually steel or Aluminum. But there are so many different types of steel. The most common used are: 45#,50#, P20,718, 718H,S136, NAK80,etc. So when you need a quote, you need to know the mold material. If you are not sure, tell you another secret: also tell them how many pcs of the product you need per year and in the future. Then the manufacturer can know how long the mold life should be, and find the most cost-effective way for you.
3) Part material
Part material means the raw material of the part or product=what raw material the part should be made of? Maybe you say plastic. Yes, of course, plastic injection molder only do with plastic, but maybe you don't know there are so many different types of plastic. The most common used are PP, PS, PC,Acrylic/PMMA PVC, PU, PET, HDPE,LDPE( just to name some of them). I don't know. Tell you a third secret: you just need to tell the manufacturer what the part is used for(=the application) and the color you want, then the manufacturer can recommend the material for you.
In addition, the part material also have something to do with the mold material. If the part material should be transparent, the mold material should be better, and the mold surface should be mirror-grade, such as S136H,NAK80,etc.
With the above elements,you can at least get an estimated mold and unit price cost from the manufacturer.