You're looking a lot of work if you don't know any cards yourself. There are plenty of places that you can look up prices, but it'll be time consuming, since a lot of sets from 10+ years ago don't even tell you if the cards are rare(worth more) or not. Here's a list of most of the cards that are worth money from that time period, there are more than this list but this has most of the cards that will most likely be in the collection.
http://www.mtggoldfish.com/prices/paper/legacy_one
If you have any pictures of some of the collection, I can eyeball it to tell if it's worth going through.
Cheers