Ask HN: Optimal shop sorting?

We have an online shop has a lot of user submitted items.

Up to now we sort by default by newest, but it's becoming a mess now, hard to find the good items.

Are there any algorithms or suggestions for best sorting?

We are considering a ranking based on:

Sort by revenue generated with a weight for age (previous 24 hours sales * 100 + previous one week sales * 30 + previous months sales * 20 + previous year * 10 or whatever)

Any suggestions?