Q: What should I do to protect my invention before I apply for a patent?
A: Shut up.
A wise man once said "Even a fish wouldn't get into trouble if he kept his mouth shut."
Many first time inventors forget about that and ruin their chances of getting a patent. Under US law, the first public disclosure of an invention starts a clock ticking down from one year, if a patent application isn't filed by then, the inventor is out of luck. Sounds harsh, but the rest of the world is even harsher. In most countries a public disclosure anytime before filing for a patent will keep a patent from issuing.
What is a public disclosure? Generally, if someone lets someone learn about their invention, and that person isn't covered by a secrecy agreement, the clock starts ticking. There are exceptions to that general rule under US law, but I certainly wouldn't rely on them without seeking a legal opinion.
Bottom line: Shut up. Talk to your attorney before talking to others.
Q: I have to test some ideas out before I'm ready to call a lawyer, what should I do during that time?
A: Start a detailed diary and regularly update it.
Hopefully you'll never need it, but having some evidence of what you've been working on can make all the difference in the world. Your goal is to create a record with sufficient detail to show a judge that the idea was yours and when the idea was "reduced to practice" (meaning that the idea has been crystallized into something that works).
There are a few reasons why you might need this information. If someone learns about your idea and tries to claim it as their own you'll want supporting evidence to back up your claim of inventorship. Similarly, if someone else independently invents the same thing after you, but gets the patent office first, you'll need to prove that it was your invention first or you'll lose your chance to get a patent.
Bottom line: Write things down.
Q: When should I talk to a patent attorney?
A: Now. Put this down and call someone.
Ideally your patent attorney is sitting next to you when you first have your idea, but that probably doesn't happen very often.
You should at least talk to a patent attorney before disclosing your invention. You should also talk to a patent attorney before spending too much to develop your idea. Many first time inventors think they need a working prototype before starting the patenting process. That isn't the case. The patent office does not require a working prototype and neither will your patent attorney. One caveat: if you have a design for something like a perpetual motion machine or a TARDIS, you're probably going to have to prove that it works.
The trouble with spending too much in research and development before talking to your patent attorney is that there might already be something out there that forecloses your chance at getting a patent.
Bottom line: Go call someone.
Q: Do I need an NDA with my patent attorney? If so, who would draft that?
Some people are scared that their patent attorney is going to steal their idea. I've never heard of that happening and an attorney would have to be pretty stupid to try that for a number of reasons.
The first reason, is that it would be a huge dereliction of the duty owed to a client and would most certainly result in disbarment. In addition, any patent would be unenforceable since it was fraudulently obtained. Attempting to exert such a patent would result in additional civil suits for antitrust violations. Lastly, the actual inventor should have notes and other evidence concerning the development of the invention before speaking with the attorney. The evidence is going to be overwhelmingly in the inventor's favor, leaving an unscrupulous patent attorney with almost no chance of escaping the horrors deserved by one that steals from a client and defrauds the government.
Bottom line: Your patent lawyer has nothing to gain and everything to lose.
Q: What does it cost to get a patent?
Hard to say, but I usually estimate $12-15k to get an application through the process.
The price varies based on factors such as the nature of the invention and what the inventor wants out of a patent. Drafting an application for an MRI machine is going to be more work than drafting one for a belt buckle. Similarly, if the inventor just wants a line on their resume, the drafting will likely be easier.
Patents can be well worth the investment. With a patent you can keep someone from making, using, or selling your invention. If the invention is a money-maker, you could find yourself shopping for a solid gold rocket-car.
On the other hand, if you don't patent your invention, and if it starts to sell, it is going to be copied, leaving you shopping for a Chevy Vega.
Bottom line: if you think the invention is going to be successful, it's worth investing in filing a patent application; if you don't think it's going to be successful why are you even reading this?