Use Newegg coupon code EMCJJGN82
Newegg has this Panasonic EW-DJ10-A Portable 2-Speed Dental Water Jet for $39.99 after instant savings. Use the coupon code to get it for $22.99. It's cordless and features 1600 pulses per minute. The same item sells at Amazon for $29.73
with an average rating of 4.2 out of 5 stars. Shipping is free.