Recommendation for Scanner

Sir,
I purchased a printed copy of your book this morning. I am looking forward to receiving it. I worked a number of years is a mechanic, but I’m not doing so currently. At this time, the time that I spend working on cars, motorcycles, etc., is for myself, my family and friends.
My experience with automotive computers, and OBD, has been very limited. I hope to learn a lot from your book.
In view of the above, would you kindly recommend a moderately priced scanner to me? Unless you would advise to the contrary, I think that a scanner that has graphic capabilities would be helpful to watch things such as oxygen sensor activity, instead of just looking at numbers.
I will appreciate any advice that you would give me. Thank you.