As a car sprayer, I should let you know that the costly part of having your bumpers painted will be removing the textured finish of the plastic (assuming you want them "smooth") it is possible but quite labour intensive, as the textured finish will need to be thoroughly sanded and primed to achieve a sufficiently thick build to be nice and smooth.
I painted two T5 bumpers, front and rear spoilers and three door handles recently for a customer. He was charged approx £500.
As for colour match, it depends on the colour. If it's metallic, it will probably be harder to match and will take more time to paint – hence more costly. If it's White, it's bound to look "fresher" for a couple of months.
Don't be put off too much though – it will look awesome!