Need to get it done. How much should it cost?

on a car ?

Yes. On a car.

I recently paid £15 to get a rear wheel on my bike trued, if that helps. A bargain compared to the swearing, frustration and wrecking of the wheel that would've occured otherwise.

20quid if it just needs a tweek

it's quicker (and free) to learn how to use a spoke key than it is to take the wheel to a shop…

Depends really. Can be around £25 for the front wheels, 4 wheel alignment can cost quite a bit more.
Places like kwick fit / national tyres can check it for free and only charge if adjustment is required.

£15 from a local tyre place in Bas Vegas.

They did it without fancy lazers, just using a bolt-on wheel-clamp looking thing.

They were able to correct a wonky steering problem in about 2 mins that had Dovercourt Ford puzzled for 6 months (after doing £400 of suspension work – 👿 )

Simple front tracking at your local tyre merchant – 15-20.
Full laser 4-wheel alignment and set up correctly – 30-100.