Script to Snap to Grid objects in Unity, so it's pixel perfect

SnapToGrid.cs

using UnityEngine;

public class SnapToGrid : MonoBehaviour {
	public float PPU = 19; // pixels per unit (your tile size)

	private void LateUpdate() {
		Vector3 position = transform.localPosition;

		position.x = (Mathf.Round(transform.parent.position.x * PPU) / PPU) - transform.parent.position.x; 
		position.y = (Mathf.Round(transform.parent.position.y * PPU) / PPU) - transform.parent.position.y;

		transform.localPosition = position;
	}
}