Some of these companies charge for the design, like a retainer or hourly. Retail places it's in the sale price of the materials or labor depending on who you go to. The construction companies and Remodelers work differently than the showroom, retail place, Independent Designer or Architect. They have different ways of charging. Usually the scope of work is what will determine the type of company you choose; sometimes you might use a few of these people on your project. Example an Architect, and a Contractor, you might need both people, A Kitchen designer works with Architects, Contractors and the Homeowner. Contractors have many ways to charge, due to the fact they supply a wide variety of materials. They can do a lump sum, a percentage of the whole project, or time and materials. The range of costs depends on the area you live in as well. The Architect can charge by the hour or lump sum, this is the same for most Kitchen/Bath Designers that are Independent.
You won't usually find the exact cost of these people online. Due to the rates vary for each region. But there are several magazines I think do a good job of giving reason expectations. Qualified Remodeler is one magazine that puts of number each year on what projects run and it shows, the return on investment % so you can gage is the project is worth it. Here is a Link to the most current issue.
Cost Vs. Value Report 2010–2011Sagging home prices, tight credit, and consumer indecision trumped lower construction costs, sending the cost-to-value ratio to its lowest level in a decade. Small replacement projects still rank high on value, but there are signs that full-scale remodeling is poised to make a comeback.
Another magazine that has recently been doing a comparison between a custom project and a basic project is Kitchen and Bath Ideas. It's not perfect but again it gives realistic costs to items involved in a kitchen. They recently have added bathrooms. They list the products and costs for each item. They show a room that needs a remodel, then do 2 designs based on the low- end budget to mid- high end budget. They show the 2 designs with illustrations and the list the products used. I think this one of the best ways to see if your numbers you are getting from people are realistic based on what you have selected. Products and scope both can change these numbers quickly so keep in mind to compare apples to apples.
Well I hope this helps to sort out the differences between the different types of companies available to you for your projects.
Angie Keyes AKBD