[userbinator]

You may want to look at some of the boards based on the AllWinner SoCs, like this one: https://www.olimex.com/Products/OLinuXino/A20/A20-OLinuXino-...

AFAIK none are currently cheaper than the RPi, but they're close and you get a lot more features along with a faster (dual-core, even) CPU.

[kale]

There are a few with quad-core. And added benefits like SATA2 connectors and NEON instruction set on the CPU. Granted that only helps if you compile against it (not likely going to help regular daily use), but if you're developing code on a small device, the gains can be huge.