[TurboHaskal]

You can do just fine with the free versions of SwiftForth and VFX Forth as long as you don't mind that they are 32bit only.

If you end up liking it and want 64bit, you can buy iForth for 100 EUR. It's what I use.

These are all amazing optimizing compilers.

If you care about OSS: Don't waste your time with GForth. If you want something simple that you can hack yourself, take a look at pforth.

[anthk]

This. Pforth works really well and the ".S" word is straightforward, while pfe is not. GForth is too difficult; altough you can code for the Game Boy with it, but in order to learn, pforth is more than enough.