we have rat bait down as we live in the country and see signs of them, we also have dogs, cats and children around. you can buy tube type things like an upside down T that you put rat bait in - available from farming type suppliers, you can get the bait there too.
I also have suffered a mouse in the house recently, it was running from roof of front porch(coming in small hole with aerial cable), under bedroom floor boards, up cavity into airing cupboard, from there into loft and down into bathroom light and it sounded like an elephant! for this we bought the electronic repellants but they didnt do any good at all, total waste money. we set an old fashioned trap in the airing cupboard and within 24 hrs it was caught. Although im a great believer of where theres one theres more we have not heard or seen sign of anything since. The electrical gadget had been in use for over 2 weeks prior to the trap, plugged in very close to airing cupboard, and yet we still heard it most days.