我对使用嵌入式硬件进行编程相对较新，尽管对编程并不陌生。我从http://microcontrollershop.com/product_info.php?products_id=5058&osCsid=9jkr9kor7d76qgvu76knsr0hp2购买了 STM32F407VGT6 多媒体板、TFT LCD、SD、加速度计、USB 。我以为我可以将 microC 用于 ARM 编译器，但将演示版本误读为 80 kb 而不是实际的 8kb。买这个花了300，我真的没有钱。我试图找到一个兼容的不同编译器，但到目前为止还没有。
我确实发现有人提到 Code Sourcery lite 可能会工作，尽管没有人提到这个特定的板，但免费版本尚未与 eclipse 集成，我无法成功集成它。
我真的不知道该怎么做，因为我宁愿不必购买全新的控制器，屏幕只是为了继续我的项目，我不想花钱购买这个编译器
如果有人知道与此板兼容的免费 IDE（即使它仅对学生免费），将不胜感激。
A compiler is required only to support the instruction set of the processor. Board specific support itself is not the responsibility of the compiler. Moreover in the case of ARM based devices, only the ARM core is the responsibility of the compiler; support for peripherals, and in particular the PLL clocking scheme for your part are also not the responsibility of the compiler. So the fact that your board is not mentioned in the documentation is largely irrelevant.
Some tool-chains and particularly IDE's from the likes of Keil (an ARM subsidiary) and IAR provide a huge amount of chip and board support. Both these companies provide demo versions, Keil's I believe is good for at least 32K, and the IDE also supports free GNU tools such as Code Sourcery, which has no restrictions on code size.
However in many cases and in particular the case of the STM32, a lot of the board support you need is available from the chip vendor. ST provide a standard peripheral library and ARM CMSIS (ARM's standardised Cortex-M support API), plus many other libraries besides. Keil actually ships ST's Standard Peripheral Library and CMSIS with its toolchain, but getting it form ST ensures the latest version. The libraries and manuals can be found ion the Design Support tab here. The board page linked in your question has a link to download example code to support the off-chip board peripherals.
So the upshot is that Code Sourcery or other ARM GCC distribution will work fine, but you may need to build your complete development environment from parts such as chip or board vendor supplied libraries plus an IDE/debugger environment such as Eclipse or uVision.
With respect to using Eclipse, there is an article here describing how to do it for the STM32 Discovery board; most of which is applicable to your board at least for building if not for debugging/flash programming - the Discovery board has a built-in STLink JTAG debugger.
Update June 2021
A lot of the above is out-of date ST have largely deprecated support for the SPL and do not even provide it for newer series such as STM32F7, replacing it with he STM32Cube framework.
Importantly however ST now provide a free IDE with a toolchain and CubeMX integrated: https://www.st.com/en/development-tools/stm32cubeide.html
你考虑过Yagarto吗？
http://www.yagarto.de/
它适用于 Windows 和 MacOS。
或 GNU ARM：
http
:
//www.gnuarm.com/ 主要在 Linux 和 MacOS 上工作（也可以通过 Cygwin 运行 Windows）。
将 code sourcery lite 添加到您的路径，以便您可以从命令行使用它，然后使用 CDT 安装 Eclipse。安装后创建新的交叉编译可执行项目。输入 arm-none-eabi （验证这是您的工具链的前缀），您应该能够编译和调试您的项目。