I've watched the Tom Avery series of tapes called Consistent Tennis Wins and found them to be great. I like how he suggests only trying to focus on 2 things when working on a stroke (no more or you'll be too psyched out). He goes over simple rules why balls go in the net or long and how you can work on developing a consistent swing. He has a series on the serve, groundstrokes, volleys and doubles play, and one dedicated to the backhand.
Either way, go on ebay or the like to find some at discounted prices.
Best of luck!