Often they can be straightened but keep in mine once buckled there will always be a weaker point so more likely to go again. Safest option is a new wheel.
I took my bent wheel to a refurb place in Bristol called 'My Alloys'.
They said that if they could straighten it and refurb it it would cost
me the sum total of £75.
They sand blasted it ready for re finishing but the guy said something
along the line of 'I'm a wheel straightener mate, not a magician'
and they returned me the wheel. They never charged me a penny
for their attempts to straighten it, nor for the sand blasting.
I had every expectation of having to give them something for their
efforts but they would not take a penny off of me.
I was very impressed and will be going back there for a refurb later in the
year. Normal refurb without straightening is £60 per wheel.
Very high quality work too.
The replacement alloy I ended up having to buy was £500.
But it was worth trying to get the first one fixed.