I can only tell you about my experience. I hired a landscape designer by the hour when a local nursery had a sale on those services. The design was then mine to keep and I was under no obligation to purchase plants or anything else. However, if I did hire them to implement the design they would deduct the cost of the design services.

A bid is when you call someone and ask them to tell you how much they charge to do a particular thing, that you have already defined. If you already had a landscape design you could get bids on implementing it from several different people, probably free of charge.

Some landscape design companies include a free consultation.

Several of the nurseries around us will do a free design. When we had ours done by 2 different venders, I requested flowering & colorful shrubs & plants. Their suggestions were very similar & we bought plants from them & others on sale. Did the labor & install ourselves. I had to give survey plan to one vender, & the other came to the house to draw & develop the plan. My niece charges $50.00 per hour. So everyone is different. Just call a couple & talk to them & learn.

It will depend on the designer you call if they are straight design they may charge a fee to come out and look at the site. I design landscapes and I work with contractors to install so I go to sites for free talk to the client and tell them approximately how much it would be for a contractor to install. Everybody has some sort of budget. Like from your idea books it looks like mostly planting for the front yard and fire pit and bench in the backyard. I design in LA so if you are near there you can call me and just tell me the size of your space and what you want and I can tell you how much it would cost. I would be glad to help if interested.