LG dvd player stops/starts while playing disc

Most repair shops have a minimum diagnostic fee of $50-75 which you'll pay even if the player can't be repaired, which isn't likely. There's no way that repairing a $100 player makes any sense unless you know exactly what the problem is and can do it yourself.

Fatparrot is right, it's worth cleaning the lens to see if it solves the problem. You can try one of the $10 cleaning discs that looks like a DVD with tiny brushes embedded in it, they're available almost anywhere that sells electronics. Sometimes that works and, even if it doesn't, you can use the disc for other players.

You can also take the cover off the player and use a cotton swab moistened lightly with alcohol to carefully clean the lens. It will be under the tray that holds the disc and look like a 3/16" glass eye. If it's not accessible, sometimes you can uncover it by plugging in the player, pushing the eject button and then unplugging the player while the tray is in the 'out' position.