The least you can buy is a QT.

 

 

Yup
You will have 400 dollars in it and nothing even started.
Wet sand them out, tape off, and have your local shop shoot it.
Not counting guns

 

 

You could have the paint mixed in a rattle can and spray it yourself then follow up with Spray Max 2K. There are several threads here with pics. If you take your time and do the prep work it looks great.

 

...... i don't know, man ....... but that bike in your sig pic looks more like Electric Blue

 

Generally-
If you buy stuff and have a few things done at a shop you can get a rapport going.
I know this shop -and I can go scratch something up and tape it off, they will shoot it .
No, they are not going to guarantee it.
But I take the risk and it is not much of one.
Most people that do not do paint jobs do not realize the work is all under the paint.
it is 99% labor and 1 % paint.
Today's paint chemistry is constantly changing.
I used to do the priming too...now not so much.
It is all very expensive to buy for a little job.
So back to the main point you can pay them to shoot your stuff.
find the right shop.

 

 

I'm sorry but I don't see how talking somebody out of 'doing' is positive in ANY way. There is nothing wrong with buying tools and trial by error.
Anybody that wants to try and learn should be encouraged to do so. I am a painter and a damn good mechanic because I am willing. You're results may vary
but you will have gained tons of knowledge and experience and you'll have the gear to do it again, and again. Painting, once you master it is an incredibly satisfying endeavor.
Nothing makes me happier than fixing or restoring something and seeing it finished in a nice glossy color like it was meant to be.

To answer your question OP a pint will probably do. By the time you add the reducer you will have a full quart. If you go ahead and buy a quart of paint
you'll have two chances to get it right