I was surprised seeing a starter make around $50 on eBay ,if you can buy the complete mower for $10 and sell the starter for $50 there's no point in fixing the mower because the parts would sell for around the same price as a repaired mower would sell for.
I've seen a few people with restored vintage mowers dismantle the mowers and sell the parts on eBay for more than they would get for the mower.