Hi there! I’ll give you input from the designer’s perspective here. First, it sounds like you need a decorator rather than a designer. In Canada there’s a big difference, designers have the legal ability to move walls etc etc as well as do the aesthetic components, whereas decorators are only allowed to do the more aesthetic side of things (paint, flooring, wall coverings, furniture, etc). I’m not sure how stringent the laws are in the USA, so I just thought I’d bring that up.
Rates: Yes, most decorators & designers work on percentage basis of your budget (typically 10%). Some charge cost plus on top of that, which means that if you order anything through them (furniture, custom built-ins, flooring, anything), they’ll charge you a mark up. That’s not really my thing. Designers and decorators typically get discounts at stores so I think a bonus of hiring a designer is getting a bit of a break on what you order through them, not a mark up. But that’s just me and something you should ask about so you don’t get any surprises later. Many designers will work hourly which is good for a small project. Expect rates starting at $75/hour, and really, the sky is the limit on the cap.
Suggestions: If you can’t afford a designer, here’s my best suggestion to you. Get a whole bunch of magazines. Ask your friends if they have old ones they want to part with, etc. Rip out pages with photos that you love, even if they’re not “house” photos. It could be colours you love together, furniture items, the feeling a photo gives you. Write a note or put a sticky on each page about what you like about it so much. Now throw those all down on the floor and see what they have in common. Get rid of the stragglers. From there, you can start to delineate what you like/don’t like, the feeling you want your home to have, styles of furniture you love, etc.
Also, stores like Crate & Barrel have design services they offer for free if you’re shopping for furniture there. Take advantage of that!!!
If there are any local home shows, check their itinerary and see if they’re offering any free “Ask a Designer” time. I’ve done those a few times and I think I’ve helped a lot of homeowners that way!
Last piece of advice: Surround yourself with what you love. If you love couches with yellow stripes but you don’t see one in a magazine, who cares?! Have a couch with yellow stripes, it’s what you love!