Do you have access to any old coverdisks from Amiga magazines? Many of these have enough software on them to boot up to a Workbench environment.
Also, there is UAEBench. It is a fully working Workbench setup consisting of shareware and freeware programs. It is legal to use and copy and works just fine until you can get your hands on a real Workbench disk. The disk image can be acquired here:
http://www.pcguru.plus.com/emu/UAEBench.zipIf all else fails, I might be able to send you a copy of UAEBench.