Probably this has been asked before, but a quick search did not seem to help, so...
My kindle is great for novels and such, but I have lots of .pdfs, .djvus and .tiffs, mostly all just scans (i.e. images of pages). Also I am kinda poor

. What is the best CHEAP solution for reading such formats? I don't mean "what devices can handle these formats" (e.g. my kindle does .pdf very badly), but rather "what do people find useful for dealing with these formats", so solutions involving file-format conversion are OK if that is the only option.
If anyone could let me know what they are using, and what their experiences are (pros/cons) that would be super-cool

. Extra points for solutions that don't break the bank!