The cost is minimal compared to the overall cost of owning the dog.
But if you want to go minimal cost, pick up several videos and couple of books. NAVHDA is good organization for GSP training and they have training books. I would recommend "How to help gun dogs train themselves" by Joan Bailey. Pre-sequel to NAVHDA bluebook.
I wouldn't worry about the barrel. It's just another method to 'finish' a dog. A day at the game farm will usually turn a dog into a bird dog. A finished dog will require more training. It all depends upon how finished you want the dog. I would forego banging pots and just wait until perhaps 6-9 months age to start bird & gun introduction. Before that yard training but let it be a pup.
A game farm is great for training. You can buy a multiple of birds in different sizes, control how they fly or set and introduce gun shots all at the same time. Take with you a check chord, starters pistol w/blanks and if you have one or borrow one, a .410.