During the past few years I've noticed couples willing to spend more money on their wedding flowers because budgets have gotten bigger or the flowers are a priority for the couple (bride).
The main thing couples don't understand about the cost of wedding flowers is the immense amount of labor involved. The florist goes to the mart, sources it all, transports in back to the studio, then has to process (unpackage, clean, cut) the flowers, prep the vases, and assemble it all. Then there is more time involved driving and setting up the flowers, and then waiting for the ceremony to end, possibly breaking down or replacing flowers to another area. Finally there's sometimes a breakdown where the florists have to come back and take it all down.
I now break out the number of hours it takes to do the flowers so that clients see the amount they're paying for labor vs materials. It's helped a lot to show in numbers the amount of time it takes, which gives the couple an awareness and new respect as to what the service entails.
If you're on a strict budget for your wedding, as many people are, here are some cost-saving tips:
Start collecting vases ahead of time- If you happen to know a florist or have a local one in your area, see if they have leftover vases from a special event they've done that you could buy for cheap. Often times for events, a florist has to buy a vase they wouldn't normally keep in stock. It can be more costly to keep these vases in storage, and the florist may just give you them to clear out space. If you're having another florist do your wedding flowers, you can give them these vases to use which will save on costs and their time sourcing them.
Focus on color - Many brides want a certain flower like a peony (which has a very short season) or anemone, instead of focusing on color. Allow your florist to use whatever is in season or cheapest that matches the color scheme you love. Color and texture count more than the actual flower used in the grand scheme of design.
Create your own centerpieces - I'm not a fan of DIY wedding flowers for the sole reason that it can take so much time and be a stress that a couple doesn't need during the week leading up to their big day. However if you do opt for simpler centerpieces, starting a few days ahead (and with the help of friends or family), I would suggest having a professional florist do the bouquets. Sometimes it takes five times to make the bouquet look just right, and that small expense of labor is definitely worth it.
Use plants - Renting plants can often be expensive. Buy plants from a wholesaler or nursery to spruce up the space, especially if there's a lot of wall space. You can then have these for your home for years on!
Reuse flowers throughout the wedding - If you are doing DIY flowers, assign two people to move around the flowers between the ceremony and reception. Use any arch/chuppah flowers to place on the sign in/escort card table. Use chair flowers to decorate the cake table. Have your bridesmaids put their bouquets in small cylinder vases to place on a head table.
Go for greenery - Using a lot of greenery in your wedding will help you save on flower costs. Creating garland down a table looks beautiful and is easy to do (I have a recipe in my book The Flower Chef for garland). For soft colors use eucalyptus and olive branches, for deeper colors, use fern and magnolia.
Spend a dollar - Go to the 99 cent store or Dollar Tree to get vases for bouquets, dishes for boutonnieres. You can't beat a dollar!