If you want information based on actual sales data, MM is what you've got. The only information a player has access to is their own guild information, as far as sales go, thus there is currently no way for MM to compile sales data beyond your guilds.

TTC (Tamriel Trade Center) is available, as well, but does not base its information off of sales; rather it bases it off of listings. It requires you to run an exe and communicates with a third party server.

There are many active trade guilds recruiting! You can find their information in the guild recruitment section.

Strictly speaking, you can simply access TTC through their website. https://us.tamrieltradecentre.com/

The addon provides some useful information to your item cards in game, but if you're looking for something to buy, the website has you covered.