Models prices

Ask H&M. You still find $40 t-shirts next to $10 5-shirts. Why? Quality

There will always be some people that only buy cheaper models. As Cargo said, quality (and your reputation as a designer) will determine how high you can push an item's price and still expect sales.

I think the price does affect the number of sales. But. For example. You can make ten sales in a month and get ten dollars from 10 customers, 1-2 of whom will want to leave negative feedback or need additional help or support, or you can make one sale and get 10 dollars from one customer and get 10 times less headache for the same money. Think about it and don't dump for the sake of sales. If the model is of good quality, they will definitely buy it. Not today, but in a month. You just have to wait.

The more exclusive a model is, the more valuable it is.