Homemade 6 inch tall stands for small floor stranders

Paint them the color of your choice!
http://www.homedepot.com/p/16-in-x-8-in-x-6-in-Concrete-Block-068H0010100100/100322580

Yep. + 1 to @yogiboy 

It's the first thing that came to mind. Easily painted/covered. Cheap. 

For, you know, temporary until you find the good ones.

same thought-

Ot these:
http://m.homedepot.com/p/10-in-x-10-in-x-10-in-Concrete-Deck-Block-55N1AN/206125490

I like that!!!  Get some of that Flex Seal rubberized paint and paint them and put extra coatings where the speaker will sit and then the bottoms shouldn't get scratched up, I would think.  

Used bookstore, a few unwanted hardcover books (encyclopedias, dictionaries, etc.), a handful of long screws. 

Thanks all, interesting stuff...

I'm thinking a few old textbooks from the basement might be just right...

That might resonate, but the long screws might be the answer.  Years ago, I was re-doing a room and used two 5 gallon cans of joint compound for a 12'' speaker stand, probably the best speaker stand I ever used.