The newest Raspberri Pi 3 is under review over at Phoronix, the Model A+ which brings new hardware at the same $25 price point as the last Model A did.  It is powered by the Broadcom BCM2837B0 SoC, with four Cortex-A53 cores running at 1.4GHz.  There is only 512MB of RAM compared to the 1GB of the $35 Model B, and there is no LAN port so make sure you know what your project's requirements are when choosing which one to purchase. 

As long as those limitations do not prevent you from using the Model A+, the performance results show this is a great deal.

"I was able to snag a Raspberry Pi 3 Model A+ for $25 with availability appearing to be better than some of the past Raspberry Pi releases. Here are some initial benchmarks of the RPi 3 Model A Plus compared to a few other ARM boards."

Here are some more Systems articles from around the web:

Systems