It will never cost what you think it will cost. I have only worked with one general contractor, who runs a permanent crew, not subs, who we had to wait for, but they got in and completed a project on time (4 months for a to the studs remodel adding 450 square feet.) and on budget. I was awe struck. they were about 30% more than the median bid. Worth every penny. I have done the same scope and had it take 8-10 months.
When it comes to hiring a designer, as much as the design fees are intimidating, we will actually SAVE you money because there is an agreed upon plan. Everything laid out, finish samples, wall paper, paint, tile, fabric. Nothing left to chance.
The most costly thing in both construction and design are change orders. Restocking fees are generally about 25% and you are also responsible for return freight.
At Eleven Coastal we have Design Packages of 10 hour increments. Those 10 hours can be spent configuring floor plans, shopping, staging, styling. A ten hour package (we can get a lot done in that 10 hours!) is $3500. Reflecting our hourly rate. Whole home design plans are a bigger commitment and based on the square footage of the project.
Do not fear, PLAN!!