Although I am new to Hoster, I've been using a set of VocoPro VHF3300 Wireless Rechargeable Mikes (~$149.95) for about 2 1/2 years and have been very pleased with them. So pleased that I added another set about a year ago. I have never had an interference problem with them. I don't use any corded Mikes.
They (two Mikes per set) use 9 volt rechargeable batteries that I buy for about $5 each at Harbor Freight and they hold up very well. I charge them well at home between shows and they hold up all night (4-5 hour show) without any problems.
These batteries hold up just as well as the Radio Shack $15 (each) batteries.
I play in small (Redneck) venues and go through 65-90 songs a night and the batteries hold up all night ... and I have never had one dropped.
KOD (Karaoke Old Dude)