I worked a product through getting patented once, had molds made, prototypes and first production run.
Google patents and USPTO.GOV can help you search to see if there is any prior art. I've heard those "bring us your invention" places are mostly scams. We used a cheaper patent lawyer and had the whole thing done for 1-2k. The drawings were provided by us in this case which made it less expensive. Really, we could have just done the whole thing ourselves and it would have only cost us the government filing fees. (~$300 range?) Took about 2 years to get the patent.
In the meantime, we had huge competitors coming out with similar products but just enough different. We didn't have the capital to fight the fight back then. Getting a patent is only as good as how well you think you will be able to defend it. (So be specific with what you are patenting. If you have a few novel ideas, maybe file multiple patents.)
Another cheap thing you can do while you are getting the patent together is put all your designs together, put it in an envelope, bring it down to the post office and have them stamp the seal with the date. That way if anyone tries to say they patented it first in the meantime, you have something with a date on it that proves you thought of it on X date. Obviously never open it unless you need to in court or something but just another thought.