I won some magic the gathering 10th edition core set booster packs, are they worth anything? Or should I open to get rare cards? Also have 2 core sets — Molimo's might and Exincar's tyranny — and a 2 player starter game that includes 2 booster packs from 10th edition.
Logically speaking, it would never make sense for the expected value of an opened pack to be higher than the value of an unopened pack. If that was ever the case, people would just buy unopened packs, open them, and sell them for a net profit. Unopened packs have the potential to have a high value, and that potential reward comes with an associated increase in cost.
You can find the higher value 10th edition cards here: http://shop.tcgplayer.com/magic/10th-edition
Packs of 10th edition have recently sold on ebay for around $8.50, if that option interests you.
The expected value of an opened pack of 10th edition, accounting only for rares values from mtgstocks.com, is about $2.38 — according to their page on the M10 set.
Your best bet is to sell the pack.