I'm having trouble finding the right #5 spindle 120mm long for this conversion for a price that isn't more than what I paid for the whole bike ($20). I've read on this forum that such spindles are $5. Where to I get such a spindle? I don't need anything fancy, just a hardened steel spindle preferably with the nuts. All I can find on eBay in that size are spindles for over $25. Any help would be appreciated!

Are there any other sources besides eBay to find old French cotterless cranksets at good prices?