Do you want something like a headset? Those are still cheaper than a lavalier.
But I think the issue comes when the Rx and Tx are involved. UHF Rx/Tx can cost a bomb, especially if hops, or is programmable, or whatever. AKG's highe end wireless Rx/Tx cost a bomb, but I think you can check out the lower end, if you're on a budget. WMS-40, I think.