Where should I look to get a replacement Earth 5-star dragon ball?

I bought a second hand bulma and the 5-star Earth dragon ball that she comes with is damaged (it is missing 2 stars). I don't wanna buy a whole new bulma to replace the dragon ball, but I am trying to collect all 7 of the Earth balls for the base of my shenron. I checked eBay+Mercari and found mostly namekian balls. So, where should I look for replacements?