Flowering Branches such as Quince or Cherry look spectacular but are perishable and are only available for a short period during the spring. Artificial branches tend to either look, well, artificial, or are very expensive.
How about combining real branches such as Natural Birch Branches, with some inexpensive silk flowers? I picked up some really cheap generic silk flowers over in the Floral District, which cost $4.50 a bundle, after checking out some more expensive options such as Cymbidium Orchids, which cost $36/stem. As you can see, these silk flowers weren't anything spectacular:
And after a few minutes of gluing...
... a pretty spectacular "faux-real" flowering branch. What makes this work so well despite using relatively cheap flowers is the fact that only a small portion of the branch is faux, while the vast majority of it is real. Now the math: One Natural Birch Branch at $.56/stem ($14.50 per bundle / 25 stems per bundle) + a few silk flowers adding up to $.25 or so + miscellaneous expenses = about $1.00. Not too bad!