Free tools are a clear advantage for any processor projects for hobbyists.
The renesas H8 (and other) processors are rather well blessed.
Renesas provide a free version of their comprehensove High-performance Embedded Workshop.
This IDE can be integrated with a number of languagage toolchains providing a single environment for editing, compiling and debugging programs.
The Renesas Flash Development Toolkit (FDT) is also free and will...