Amazon Warehouse offers Prime members the used SanDisk Extreme Plus 32GB Class 10 UHS-1 Secure Digital High-Capacity Card, model no. SDSDXS-032G-X46, for $23.26 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise shipping costs $8.) That's $32 under the lowest total price we could find for a new one elsewhere. It features up to 60MB/s write speeds and 80MB/s read speeds.

Note that no warranty information is provided.