Desertsun is sort of right, there is no "Construction Season" any more. Greed and dumbness have pushed the unwilling to do the impossible.
The Xmas holidays are always prime, always have been. Nobody wants you around their house then, business gets real difficult to find, Thanksgiving till after New Years. Most good contractors try to bulk up their work list to have a back log to attempt to carry themselves thru that period. Doesn't always work, that is also the time when most contractors need "Extra Money", momma does not want to hear that business, there is no work.
I don't know material costs are going up. Just bought some pressure treated stuff, prices were down.
One sure fired way is get involved with the design, buy the materials yourself. Get some engineering type to do the design, set of plans and give a bill of material. Buy all the materials and have it sitting on site. Hint, use your credit card with a Reward Program and get that extra 2% kicked back in your pocket. Bargin very, very hard for everything. Example I just got a 20% discount from Lowes over the Memorial Day sale, never pay retail.
Then you only have the problem of getting the contractor to supply labor to build it too your plans. Very easy to judge what is going on, if you require a fixed price quote for the job. The sticky wicket is always getting a superior design, excellent craftsmanship. Many contractors will not give a superior design, so you can also make out that way too. Craftsmanship is a pig wallow in today's World.
Same problem as always, you must find somebody hungry and good. Make them compete strongly for the next meal.
For me, DIY is the only game in town. You control the prices, you control the design, you control the craftsmanship.