Amazon[amazon.com] has the Zinus Cynthia 14 Inch MyEuro SmartBase / Wooden Slat / Mattress Foundation / Platform Bed Frame / Box Spring Replacement, Full for $53.41 (27% off) w/free shipping for Prime members.
Bought this for my daughter's new memory foam mattress a year ago, and it has been headache-free. Easy assembly; sturdy construction; no issues whatsoever. Current price is about as low as it has dropped in the past year or so, and $4 off the all-time low. Highly recommend.
Fits Full size mattresses.
Complete mattress support system - replacing both the frame & box spring
Easy to assemble in minutes / no tools required / not compatible with head board brackets
14 wooden slats, center support bar and seven foldable legs provide strength and stability
Foam padded tape is added to the steel frame for noise-free use. Folds in half for easy storage and transport
12.5 inches of clearance under the frame for valuable under bed storage space