* "Peter Piper picked a peck of pickled peppers." This one is quite simple, but it can get tricky with the repetition of "p" sounds.
* "She sells seashells by the seashore." This one has a nice rhythm and uses common sounds, making it relatively straightforward.
* "Betty Botter bought some butter, but the butter Betty Botter bought was bitter." This one has some repetition, but the words are relatively simple and easy to pronounce.
Ultimately, the "easiest" tongue twister depends on the individual. Some people might find one easier than another based on their native language, experience with tongue twisters, or individual speech patterns.