Not knowing the specifics of the idea or the product, I would assume that the US is the largest market. If that is the case then your best bang for buck is to do an initial filing yourself for a US patent, the initial filing date serves as the reference data if someone else tries to do patent the same idea. I believe you have 3 years to finish the US patent from the initial filing date. Once you do an initial filing, the idea is considered as public knowledge, I think you have another 3 years to file a patent in other countries.
The initial filing you can do yourself in some half assed manner, the final patent application should be done with care and probably by a professional.
You need big bucks to defend a patent, and big bucks to file a world wide patent. A patent is not a vehicle for generating money, it serves mostly to mitigate the risk of a very successful product being ripped off, now if you product is not very successful then having a patent or not is about equivalent.
What I would do is try to do as much work on the product myself, if I need to get others involved then I would do an initial US patent filing then get others involved, from that point I have 3 years to make money off the idea so to pay someone to finish the patent application and file for patents in other countries.
If the product is labor intensive then you will have to get it made in a 3rd world country like China/India, if the value of the product is primarily based on the materials; aluminium,steel,silver, etc.... then get it made locally as commodity prices for materials is the same everywhere. If the product is heavy then, you have to decide if the shipping costs from overseas + associated risks and headaches is worth it vs locally made.
For product development, I have no advice. I develop my own products, I once worked with a company in Tiawan to get my product made, it took a year of me drawing pictures to get the product into a state ready for production. For stuff like electronics, everything is regimented, structured and streamlined, I just send them CAD files and a parts list and they know how to handle the rest. Outside of electronics in which things are not as structured and regimented then you will have to talk them in which case things will move at a snails pace due to the language barrier and when it does move it is often in the wrong direction.