StateoftheUterus we also thought about buying a ready-trained gundog. Prices are very high, I think at least 4-6k for a quality dog.
We were very nervous that, as beginners, we'd not cope with the demands of a puppy and training. However, we took the advice of my cousin (a gundog trainer) and various other enthusiasts of working breeds that there's nothing like the bond you share with a dog you've had from a pup, and took the plunge.
Anyhow, a year later, we have a scrummy adolescent Labrador lazing on the sofa, and it has been an absolute joy. Kids are 10 and 12 and it is wonderful to see the love they have for him (they are terrible dog trainers though, highly inconsistent and just lob ham at him for doing practically nothing!). He is sometimes hard work, and I've stopped counting the things he's chewed up. But we have trained him ourselves (with help from puppy classes and Zoom classes when that wasn't possible) and they are absolutely right about the depth of the bond. He's now a polite and friendly chap who wants to please.
We always imagined we were capable of the bare minimum of training but now DDog enjoys Saturday gundog puppy sessions with DH and Sunday agility beginners sessions with me and DS, who has loved learning to run with him. He loves the kids, they love him and it's all good. We couldn't wish for a better dog (well, perhaps one that doesn't roll in fox shit and steal cheese....)
We found the Pupp Squeezy books helpful and if you get a gundog, the Pet Gundog Puppy book is great. We also swear by Total Recall, and our dog's recall is now almost there.
Puppies are a nightmare at times, but it is worth it in the end. Good Luck!