Guess it all depends on what you mean by "inexpensive". If you just want straight plastic indys to replace it with, those are easy to find, just look for Panther tracks. Your other options are to find someone with vinyl, contact Tamiya for replacements (won't be cheap), or go with resin such as ModelKasten or white metal such as Fruilmodel as replacements but they won't be cheap either.
Sorry to hear about your predicament. Hopefully someone will come along with a spare set and you won't have to dish out major $$ to get replacements.