Ebay offers 12"x12"x2" Mushroom Acoustic Panel 24-Pack for $19.99 with free shipping.


Product Description:
The Soundproofing Wall Padding is produced by environmentally polyurethane foam.In order to improve the opening steps and   
specific acoustic characteristics, make it not only has the sound absorption characteristics effectively, without any harm to human body.and Great for spot treating sound on walls in your studio or office - For use in recording studios, control rooms, Offices home studios, home entertainment theaters, Home Offices.
Features:   

•  Mushroom style angled design ensures optimum sound absorbency.   
•  Create a great listening or recording environment with the best value noise reduction products. SoundAssured foam squares are a low cost solution to get better recordings at home or in the studio.   
•  12 Pack Covers 12 Square Feet - Each tile is 1 square foot of 2 inch thick acoustic Mushroom.    
•  Reduce Unwanted Noise And Echo - The panels help reduce reverb, flutter echoes, undesirable acoustic reflections, unwanted noises and are best for small to medium size rooms, theater rooms, recording studios, churches, or offices.   
•  Make Higher Quality Audio and Video Recording - Improving your audio quality instantly by reducing background noise and echo while recording your voice overs, music, interviews, podcasts, or YouTube videos.   
•  Use to spot treat a professional or home recording studio, commercial or home office, rehearsal space, or home theatre. Easy to shape and cut to size, altering won't affect performance.   
•  Acoustic panels are used for professional studios, rehearsal rooms, concert halls, podcasting, churches, home theaters, vocal booths, home studios, offices, man caves, dog kennels, utility closets, and more.