You can use a stack of books to elevate the speakers. It's not the ideal speaker stand but it is better than nothing. For what it's worth, I think those iso-acoustics desktop speaker stands that are popular are very over-priced. Here are some affordable alternatives that look decent:
Technical Pro 8,
Universal Desktop, and here is one that looks pretty good for larger speakers:
Workstream by Monoprice, although that is meant for video monitors, it looks about perfect for some o the larger loudspeaker monitors. Desktop speaker stands are something that could be done real easy as a DIY project as well.