I am actually a floral designer, and one of the most important components of pricing is what type of floral you are using. Floral markets fluctuate- flowers rise and fall in price due to whether or not they are in season, rare, tropicals, etc. A cascade requires a lot more work than a more standard style.
The bouquet you love is a pricey one =) Sorry to break it to you, but if you get that for under $250- $300- you found a bargain. There are a LOT of orchids in this picture. I see purple dendros, green cymbidiums, and maybe some purple mokaras peeking out in there. Several different shades of purple roses, miniture callas and purple lisianthus. There may or may not be some deep purple hydrangea in there… hard to tell! I love the monochromatic deep purple! All orchids are expensive, specialty roses like those are pricey and have minimum orders that unless you are using them across the board and the florist is order in bulk, she more than likely has a MINIMUM order of 25 stems… of each color and type… which you end up paying for. Specifically you could ask your florist what types of “filler flowers”she would recommend to work the price down. If a bride came to me with your request, I would try to steer in that direction to be budget friendly if it was a concern.
Some alternatives that you could use to achieve the same look cheaper:
I would build my bouquet base (color, texture and shape) from cheap flowers (Hydrangea, stock, and carns) and then add the expensive guys (orchids and roses) sparingly for the same look (literally, 3-5 each could suffice if well placed).
I would use one or two deep purple or cobalt hydrangea (these are actually more expensive than white, green, or light blue hyd. but will give you a LOT of coverage (two can practically MAKE an entire bouquet!), so it works out cheaper, know what i mean?), keep the deep purple lisianthus as in pic, its inexpensive and in that saturated color palate, has cool buds too. Purple stock is a great alternative!! Opt to use- carnations!! (dont gag!) They are available in several shades of purple to give you that variation like the roses in the pic. Available full sized and mini in fact. And you could throw in ONE color of purple rose to give you the textural effect you like- “spray” roses are a bargain. the smaller miniture ones… get a lot of mileage out of one bunch for bouquet and boutonniere purposes.
NOW- for the cascade. I would recommend you request a “cascade or trailing look” with PHALAENOPSIS orchid. This isnt a cheap one, but its WORTH it. Show stoppers! each stem has multiple large blooms. your florist can incorporate them into the entire bouquet (only wiring 3-5 individual blooms, rather than a true cascade where she may wire 20 or more!) and when left on the natural stem, they will create a natural waterfall down the front. (NO wiring, adjusting and less labor cost over all.)… and IMHO, a more contemporary take on the classic cascade. HTH!
Purple Phalaenopsis Orchid (this is likely about 4 stems)