Start with story-first books
If you are new to classics, start with books that move quickly and have a clear narrative hook: Animal Farm, The Great Gatsby, The Old Man and the Sea, The Strange Case of Dr. Jekyll and Mr. Hyde, or The Time Machine.
Move into richer novels
After a few short classics, try Pride and Prejudice, Jane Eyre, Treasure Island, Little Women, or The Picture of Dorian Gray. These books give you stronger character work without becoming too heavy at the start.
Check editions carefully
Classics often have many editions, abridged versions, deluxe hardbacks, and bundled sets. For price comparison, the safest first match is usually a normal paperback of the base work.