The Phenyx Pro ptm-10 has been the best bang for your buck stereo IEM I've found.
Phenyx Pro UHF Stereo Wireless in Ear Monitor System, Wireless IEM, 900MHz Band Selectable Frequency, Rack Mountable, 160 ft. Operation, Ideal for Stage, Studio, Exhibit, Lecture, Speech (PTM-10) https://a.co/d/ifW5cAr