Power Droid from the Vintage Star Wars line was about as basic a toy as you could get from this line, yet everyone loves this guy. He's a little blue box with two movable legs and some stickers. He also has a tiny rubber antenna on his back corner. This is often missing, and on mine (pictured below) that top cylindrical part is missing from the square base. Perhaps his best feature is the little clicking sound Power Droid makes when you move his legs.
As a kid my buddy Derek and I used to always have Power Droid walking around Jabba's Palace. We would pretend the Gamorrean Guards would think he was a mini-fridge and open his front panel looking for soda. They'd always be disappointed to just find circuits.