Need to have an advanced search filter of my digital products - don't know how?

[dragonfly2]

Hi,

I'm creating a personal photography website to sell my photos. And I'm using Easy Digital Downloads to sell my digital products on Wordpress.

Basically I want customers to be able to search digital photos that are:
- most downloaded/purchased
- best rated
- by price etc

but don't know how to set this up on my site..as there isn't this option in easy digital downloads

Also, I'm going to have some images that are free to download but would like a customer to be able to say search 'black cat' in ONLY the free images I have on the site. Or 'black cat' in ONLY the commercial images for sale if they like. But no idea how to set this up or do this?

For example on Stock Photos, Royalty-Free Images & Video By Dreamstime a user can search in the free images section or the commercial section if they choose. This is the kind of thing I'd like be able to do on my personal site. But I have no idea where to start?

Right now I have categories and tags set as I upload my photograph. But these taxonomies only allow sorting of ALL the images I have as a whole. Which I also need categories/tags as they are so people can find what they're after like a 'black cat'. e.g. so the category is 'Animals' and the tags are #black #cat

Thanks for any suggestions and help