This is an idea for a bridal bouquet. They are white anemones with black feathers. The center of the anemones is slightly black, so it complements the feathers well.
In this bouquet, white calla lilies, white dahlias and black cosmos. The cosmos are not really black but rather of the Chocolate Cosmos kind, the color is close to black.
Black and White Tablesetting
For centerpieces, you can have an all white centerpiece, on black tabletops, like in this tablesetting. You can see white calla lilies with white dendrobium orchids in the centerpiece.
The glass containers are lined with black ribbon.

You could also have an all white top of a glass arrangement, with black paper or cloth lining the glass walls, like this one.

The flowers used are white roses with ornithogalum.
Black and White Boutonniere

Here, I have made a groom's boutonniere using white gerbera daisies with black centers to complement the black and white wedding theme beautifully. I wanted to make this design as simple and elegant possible. The gerbera daisy itself is already a large bloom, so I didn't want to complicate things. I only added different sized two loops of beargrass just so to have some lines in the boutonniere. Then, for the accent, I used a black and white striped ribbon. I hope you like this elegant boutonniere.
What Other Flowers To Use?
In terms of flower choices for this wedding theme, you don't have plenty but enough to make your black and white wedding theme special.
You can use burgundy scabiosas with white peonies in your round bouquet. For the groom's boutonniere, you can use a single burgundy scabiosa with white ribbon. For centerpieces, you can add to white peonies, add white roses or white lisianthus to make a low round centerpieces.
Another flower combination is using black calla lilies with white hydrangeas. This is a great combination, the fluffiness of the hydrangea petals with the rigid blooms of the calla lilies make a great texture for your bridal bouquet.
There is also a gerbera daisy variety, which has white petals and black centers. Use them with black and white polka dot ribbon to make lovely bouquets, centerpieces and boutonnieres.
If you like a traditional look, you can choose white roses with black privet berries and make a hand tied bouquet. Decorate the bouquet and centerpiece with a bling bling embellishment. Use a bouquet buckle, or rhinestones to bring up the appearance of the flowers.
For cheap wedding flowers, you can use just gypsophilias in your wedding flower arrangements, but complement with black and white satin ribbon, or black ribbon with white lace ribbon.
Check out the flower arrangements in other wedding themes...