This question comes from Rory, an entrepreneur hailing from Jamaica. (ya mon!)
How much does it cost to incorporate?

I have incorporated both a C Corp and LLC.

C Corp - Nevada (no state biz income tax)
LLC - Missouri (where my co-founder lives)

C Corp - about $600 initial setup, $200 yearly or so
LLC - about the same

This is using off the shelf type of deals, no custom specialization from a fancy lawyer.

Nevada C Corp

This was through Amerilawyer (or Spiegel & Utrera, PA). It was simple enough to get everything setup. They also offer address forwarding services, so even if you live in Arizona or California, you can incorporate in Nevada and have your corporate mail forwarded through them.

LLC out of Missouri

This was through MyCorporation and was also very painless. Their phone reps must’ve been out of SoCal because the guy who setup my LLC kept calling me “boss” and saying “killer, bro”.

Pricing tricks of the trade

All of these off-the-shelf type of incorporation sites advertise really low fees. But once you start talking to them, you realize there are a few more things that you pretty much have to have to actually run a business. (Lawyer filing fees + State filing fees + Corporate seal fees, etc)

When to Incorporate

I advise only incorporating once you have a significant amount of revenue coming in from your business or if you need to protect yourself from potential liabilities early on. Anywhere from a thousand to several thousand a month might be a good range, depending on your tax situation.