Do you have floor speakers or a surround system with speakers? Television speakers or those found on laptops aren't going to be of sufficient quality to make the effort worthwhile. Still, maybe my expectations are much higher than yours. Some televisions might have good enough sound for the most basic, entry level karaoke, as long as your expectations are realistic.
As a cheap way to go, if you already have speakers or your television has good enough sound for what you want, this is probably the least expensive solution:
This:
http/www.amazon.com/Pyle-Pro-PDWM2100-Professional-Wireless-Microphone/dp/B003GEJ5SK/ref=lp_11974731_1_1?s=musical-instruments&ie=UTF8&qid=1460914507&sr=1-1
and use it with a 1/4" to 3.5mm adapter which is available at any music supply center or sound shop. Probably most electronics stores too, and run it all through your laptop to your tv or home theatre system.
Or, if you want to spend a bit more, you can go with something like this, and plug your mics right into the unit.
http
/www.ebay.com/itm/VITEK-VK350-DVD-MIDI-KARAOKE-PLAYER-/272197462753