Do we have any Karaoke Gurus out there?

First off let me go on record as saying that I hate karaoke and all things involved with it. But Mom loves it, she goes once or twice a week (three and four times in the summer). She has a boatload of CDs and a karaoke machine that she spends hours on.

Well, my brother gets her a new karaoke "Singing Machine" for Christmas and now I am tasked with making it work. It doesn't play CDs so none of her library will work. I have to install a program on her laptop and then download songs from the internet and then install them on a USB drive and then plug the USB drive into the "Singing Machine" for her to have any songs to sing.

But it does have a Bluetooth feature to where I could connect her phone or tablet to it and play songs from it. So what I'm asking for; is there any advice on apps to download on her phone or tablet so that she can play them there and also use her new "Singing Machine".

Thank you for your help.