Hi - my bike (purchased in 2007) came with this - FSA Omega MegaExo Triple, w/Integrated spindle, 30/39/50T. I bought one of these a few years ago, possibly the last one in the world, to replace it. It needs replacing again. What do I do now? - they don't make it anymore, I would prefer not to buy a whole new groupset.

Why does it need replacing? If the bearings are bad, replace the bearings. If the rings are bad, replace the rings. If you’ve bent the crank arms, stop crashing

If you know what your BB shell type is, then you likely can find many other cranks.

But I do agree with the first response to your thread. What make and model bike you have and the brand and series drivetrain components on it can help get a better answer too. Along with why you think you need to replace the entire crank.

i just searched: "50-39-30 triple crankset" and a long list of them came up.

just get the correct BB to match the crankset, and install it... minor adjustment of the front der. may be needed, but it might even work, as is!

personally, i prefer Shimano HT2 cranksets over FSA stuff anyway.

what made you assume that you'd need an entire new group, anyway?
what parts are on the bike now?

2007 Fuji Professional 3.0
still has same spec as when purchased - 105 front and rear mech, 9-speed
I thought that finding replacement chainrings would be even harder than finding a replacement crankset

I recommend a used 6500 Ultegra Triple. Plenty available, standard style + quality replacement chainrings are still available from Stronglight and TA. https://www.bing.com/search?pglt=297...EESS&PC=SCOOBE You'll need a Shimano Octalink BB still available new from under $20 and up for higher tier versions. https://www.performancebike.com/shim...69365?v=468059

The 9 speed cranks for Dura ace, Ultegra & 105 uses Octalink V1 BBs. Not the same as the BB-ES300 series. These have different spline patterns and are not interchangeable. Putting a V1 on the ES series will destroy the interface. See attached for some of the V1s models.

The new Octalink V1 that is needed is the BB-5500 series, in 118mm size for a triple.

Sorry, I goofed on that one.^^^^

You really shouldn’t need to replace all of the chainrings at once nor, for that matter, need to replace the chainrings all that often. Chainrings last many times what a rear cassette does and a rear cassette will last, roughly, 9000 to 15,000 miles. Chainrings should last tens of thousands of miles.

As has already been mentioned, you really shouldn't have a need to replace all the chainrings at once. It's probably just the ring you spend the majority of your time in that'll be worn, usually the middle chainring on a triple.
Lots of options for replacement chainrings out there in just about any tooth count you can think of. Google or ebay the tooth count you want and make sure you're getting the correct BCD (bolt circle diameter) and that it's the correct number of arms/bolt holes (4 or 5 arm) and get whichever one suits your fancy. Low mileage used ones can be found pretty cheap on ebay. Depending on the area you live in and the kind of bicycles are prevalent, your local bike co-op (if you have one) might have what you need for dirt cheap.
If you're replacing the middle or large chainring, you can usually even remove those without removing the entire crank though pulling the crank typically isn't all that hard.