Whatever you do, don't use a spray can.
You'll just have a bigger mess to clean up later.
You can get acrylic enamel for $50.00.
It's not great but compared to a spray can, it's fabulous.
Probably cheaper too.
I would recommend for under $100.00 use a urethane.
(The whole "kit" is less than $200.00, w/ primer and clear)
They have some nice colors and it's pretty tough stuff.
Far better than enamel.
If you can't afford that, you can't afford to paint your car.