Is there any advantage to taking, say, a Motrin 600mg(which are pretty expensive), as opposed to taking 3 normal Motrin 200mg?

Absolutely none. Your doctor should have told you this.

I would not think so if you can buy 3 - 200mg cheaper than the 1 - 600mg.

Nope. Only for the pharmaceutical company.

I usually take the generic which a doctor and a pharmacist told me were just the same and any combo you want to make up your dose, it didn't matter. We were trying to keep costs down so they all knew what we were trying to do. And the dose Keith needed to take was much higher than the OTC pills but it was cheaper that way than the prescription ones at the correct dosage pill. We went with the cheap:-)

The only advantage is getting it as a prescription - which can be less that over-the-counter, depending on your insurance plan.

I don't see how. Unless you own stock in Motrin. :P

As I recall 600MG Motrin is prescription strength, the advantage is that your doctor considers your health condition and the effect that dose might have on your heart or your possibility of ulcers, among other side effects before prescribing it. I don't take Motrin but I doubt very much that the recommended dose listed on the 200MG bottle is ever for 3 tabs/600MGs and taking that amount on your own seems ill advised. Too many people think that if X amount of a medication is good... then X, plus more is better. That's not wise. Examples: too many aspirin will produce ulcers. Plain old water; you can't live without X amount of water but drinking X, plus a lot more water will definitely kill you.
Motrin without the expense of the name is ibuprofen and is considerably cheaper... especially at warehouse stores like Cxxtco or Sxms Clxb.

I don't think so.