What a timely topic! We'll be posting the results of our photo survey in a few days, where some of these issues may also be addressed. (So be sure to be on the look-out for that!)
In the meantime, yes, I have hired a food photographer, twice, to shoot the photos for my two books. It can be very expensive ($8000 for a three- or four-day shoot covering 30-40 projects and no more than 100-150 finished photos). The photographer was paid out of my book advance from the publisher, but these were the going rates about 9-11 years ago. I also did all of the food styling and setups myself. If you aren't going to do that part, you'll have to pay more. I hired a pro and you could, of course, probably find a good student photographer to do your work more cheaply, so this is just one benchmark.
Once I got into more cookie work and had to market my work more regularly, I decided I couldn't afford a pro, or the lack of control that went with hiring one (having to shoot to their time schedule, for instance). So I bought a digital camera. I really like mine - I shoot on semi-auto mode, so it does much of the photo-thinking for me, though I still need to be quite mindful of lighting (setting up white boards to bounce light and control lighting balance) and the overall staging. I take a lot of time with both of these things, often taking an entire day to shoot one cookie project for my videos and marketing needs. The camera I have is a Canon EOS Rebel SL2 EOS 200D. Pretty user-friendly. I find I most often shoot in landscape mode to get the most depth of field (especially needed for large 3-D cookies). My only complaint is that I haven't figured out how to get a completely crisp depth of field, as even elements in near-background are rather fuzzy in the landscape mode.
Hope this helps a bit. I recommend doing it yourself, and getting a user-friendly digital camera (where you can operate semi-automatically) AND also capture images in raw mode to allow for maximum editing capability. Phones don't store as much data with each image, and so phone images are harder to correct (for lighting, shadows, etc.) in Photoshop.