Brother, she is not worth what she doth cost
The keeping. (2.2.51-52)
Hector and his brothers and father spend a whole lot of time arguing about whether or not Helen has any "value" to them and whether or not she's "worth" all the lives that have been sacrificed to the war. Wow, talk about familial love.
What's aught but as 'tis valued? (2.2.52)
Highlighter time, because this passage is super important. Here, Troilus argues that a person's "value" is in the eye of the beholder or, the person doing the valuing. According to Troilus, nothing has an inherent value that is automatically built in from the get-go. It depends on what it's worth to the people who take it upon themselves to assign value to it. In other words, Troilus argues that Helen's "worth" depends on whether or not the Trojans "value" her. (Kind of like a skateboard or a bike that can be won on eBay if you think it's worth more than what other people are willing to bid.) That's a pretty depressing and dangerous thought. This basically explains how and why the Greeks and Trojans can treat people (especially women) like objects that can be stolen, bought, and bartered for.
We turn not back the silks upon the merchant
When we have soil'd them, (2.2.69-70)
Here, Troilus compares Helen to some silk fabric that's been stained. The idea is that Helen is like a product in the marketplace that can be bought, sold, and stolen—and ruined by previous owners. The "soil" suggests that her sex life has somehow ruined her.