Holluwoodnvegas is right, try to alternate places to train, parks, other peoples houses, pet stores etc...
Do you have other friends with dogs? Train in front of their dogs, or get together & have your own little training sessions.

I think the doggy day care is great, especially if your not able to participate in a class.

Target has the treat bags, for $4something. Petstores have them too, but usually a bit more expensive.