Low cost speakers for HDTV

First I am looking to spend not much more than $20 for speakers.
I've read quite a few post regarding this issue but have not seen one that seems to answer my question. How and What kind of speakers can be used externally for my 32 inch Vizio TV. I do not have a 3.5 audio jack but I do have a optical cable audio out jack. I do have standard RCA cable audio out ports. The optical cable , while a good idea does not seem to be available in other than a sound bar, which is pricey and to big. All the small speaker sets that are used with PCs need a 3.5 jack. I am looking for speakers that use RCA jacks but they don't seem available either. The only options seem to be some kind of converter, which are bulky . There must be some kind of very simple speakers for my set up but I have not been able to find them. Does anyone have suggestion?

Thanks