Don't let finances determine your goals, and whatever you do don't fall into a rut of trying to train with sole use of a forum as your only resource.
In your situation it's easy to" cave in" to when and where your dog "wants" to retrieve. Don't do it.
You'll be better off in the long run if for now,.. to strike a good balance between retrieving on land and where your pup "wants" to retrieve. ..in water.
Get things straight on land first, then move to water. No need for tons of meaningless marks either.
Cut some grass this spring, maybe you can make a little pluck and get yourself some good proven, comprehensive training material.
Good luck to you!