I guess people do it differently in different areas of the country. And there are definitely some companies in my area who do cheap designs or even free designs at times.
But for the most part, if you aren't charging at least $600-$700 for a good landscape design, your kind of a hack - in my area. Most professional landscape companies or landscape designers charge at least $750-$1000 and the average is closer to $1250-$1500 for a full front yard or full back yard design. I know a few designers around here who are closer to $2000+ for every design they do.
The designer we use is a little less expensive than most because she has almost no overhead. She doesn't have to advertise because we send her over 100 designs a year. She doesn't do home expos, no internet advertising, no display garden, etc. These are all things that most landscape designers in our area usually do to get work. So because she has none of these expenses and works out of a small studio in her house, she's more in the $650-$950 range. And that's cheap for our area.
Now maybe what we mean by landscape design and what you all mean by landscape design are different. Typically, one of our landscape designs take about 15 hours to do, with time on property discussing the clients wishes, taking measurements, drive time, and design time. So even if you just charge a low rate of $50 per hour, that equates to $750.00. If you're getting a lot less than that, either you're doing much more simple designs or you just don't value your time as much as we do.
A typical landscape design we would do for this price would look something like this one;
In my opinion, if someone isn't willing to invest that kind of money into a design, how are you going to get a $20K or $30K job out of them? One of the good things about charging a fair amount for your designs is that it's a good indicator that the client is serious, has money, and is willing to invest in the process. So your chances of landing that job is WAY higher for that person than for someone who is only willing to pay $150.