I think that in the US you may get a patent lawyer on side for a share of the profits (no win no fee?).
In other countries the situation will be different.
I personally have a different view of the patent situation.
To my mind a patent is only worth the money you can afford to spend in litigation protecting your product, it is not a protection in itself, at least, not much. If you don't protect it no one else will. It isn't as if you can report infingements to the authorities and they will prosecute for you.
In fact, since some companies spend significant sums on patent searches and taking out a patent may actually make things worse by publicising the idea before you are placed to gain sufficient revenue to defend to defend it. Remember, there is a long way between the idea and sales. You may need tto protect the idea during this time by other means and protect the working life of the patent.
If you can bring your product to market by yourself then it doesn't automatically mean it is the best route to success, though there are plenty of examples of successful entrepenuers who have done this.
Sometimes the success of a product is time to market and the ability to match supply to demand. A small start up company may find this difficult for others it is no problem to scale growth to the growth in market demand.
If you have or can acquire all the necessary skills, personel and an infrastructure to successfully manufacture and sell the product, go for it; especially if you have found a niche with no direct or imediate competition. However, if there is a need for your product then there is probably something established that provides a partial solution. It may be far better then to defuse your competition by licensing them to manufacture and market under their brand name.
Not always a sure fire approach; look at Dyson and his confrontation with Hoover, for example. His initial problem was they weren't interested so he decided to manufacture himself; nothing grabs attention like competition, so then they became interested and have spent more money, probably, on finding ways round his patents than if they'd licenced the design from him and on infringement suits.
This "not invented here" syndrome is common.
For some years I touted around a new Vortex meter design and was usually told that it wouldn't work or be practical or useful but nevcer that it "wasn't invented here". To be fair, in some cases the reasons for not wanting to take the design were strategic. If your product is too close to one they already have, then they may wish to protect their investment but not taking your idea on board and trusting no one esle will either.
However, one company I offered it to had the grace to copy me, with an appology, a copy of a recent research project at a US university that basically "re-dicovered" what I'd already done.
I have another meter design under consideration with a manufacturer under a confidentiality agreement. It may yet go nowhere but I have learned something from my previous mistakes. Your idea is a product like any other and needs to be "sold" and marketted just right.
The value of a patent to me? none. It would have been money spent to publicise the idea to others. Better for me to get a manufacturer interested and then use their skills to build a better patent than I could or a patent lawyer could (you can't expect them to be technically competent).
Much depends on what your product is and what you expect from it.
If it is something you can afford to bring to the market yourself, you may feel that patent protection is an essential to give some protection against the more ethical companies, you may find you have none that you can afford, against the unethical.
For the others, you may find that you just have to accept that your idea will be copied and live with it, or at least, with the share of the market you can access for yourself. Of course, you may find a patent lawyer ready to take an infringement case on a contingency fee.
If you don't patent, no one else can once you are in the market (public domain) except if they think up a new angle they can patent and thus deprive you of the opportunity to profit yourself. You might also look and see if you can have other protection such as copywright or trademark. Sometimes the best protection is to build sales and brand recognition and rely on the loyalty of your customers for your profit.
The key point is that nothing is going to guarantee you a monopoly for the life of the patent. If its really good and profitable then some one else with either ignore your patent or find a way round it "so sue me". It may costyou more to defend than it ever makes in profit. However, a patent is not itself an expensive option and when you should get it is probably more important than if. After that it's upto you how you use the patent.
In any event the best course is research.
There are plenty of "inventors" societies available to provide general advise and many are on the web. Some patent agencies also "suggest" where you can get such advise or help. Many warn against some of the companies that offer to "help you get to manufacturing" be warned, not everyone out there is a nice person with your interests at heart.
There are, I suppose, as many bad news stories as there are good news so there is no one answer, the best advise for your own ideas is the same as for anything else, do the research, and prepare. Do not mislead yourslef as to the merits of the ideas nor your own capabilities, get a reality check.
JMW