For production growing, I only recommend one source and that is a bare-root dormant grape vine from a certified Nursery. I have had tremendous success rate of practically 100% when planting these vines.
As for finding out which nursery to go with, simply searching online will give you a listing of nurseries in your area. Don’t worry though, they can ship. I get my vines from Niagara and the winery is in Prince Edward Island.
I would also take it a step further and ask the wineries in the area who they would recommend. Generally by now, most nurseries in the business are of great quality. All of the bad ones seem to have gone away.
Your other ways are getting a live potted plant. This way, you can simply transplant the grape vine into the desired location. This is the next best solution however, it does have a much lower success rate. It can take a while for a vine to adjust to its new environment and if it’s hot when you are transplanting you will have limited success. I would only recommend this method for experimental purposes. Either that or if someone is giving you a vine for free!
The third way is propagating a grape vine. This is basically taking on the first step of growing a grape vine (normally what a nurseries would do). This I will cover in another post but, I will just point out that I would only recommend doing this for experimental purposes. It’s a great practice for learning how a grape vine grows but, at a small scale, it is likely more economical just to buy the grape vine.