I think what you need is 300 bumper stickers. That should hide the crack nicely.
A junk yard is probably your best bet for a new bumper cheap. I would have it painted by a local auto body shop though, If you have it painted off of the car the color won't match nearly as well. Remember, paint fades over time and when you replace a panel or a bumper you have to try and alter the paint mix to make it match up.
You'll never do it perfectly, but it will look much better if it's done at a good local shop.
There are multiple ways to approach the problem;I autoX and I find small problems in some of my bumpers a lot. Going to a local shop and having them do everything(purchasing part, painting, installing, etc.) is the most expensive way but also the best results. Going to an online company/e-bay or like previously stated to a salvage yard you should be able to find a bumper(especially for a civic, OEM or aftermarket) very easily, you could order it unpainted and then goto a local shop and have them match the paint, this way produces the same results for cheaper. And the third way which I prefer is to patch it yourself(if you need some ideas how to do this just post a pic of the damage and I'll try my best to describe a good way to go about fixing it), and then use some touch up paint or if it is fairly large damaged area fix it yourself and then take it to the shop to paint it.