I wouldn't spend cash/coins on packs honestly.
Some are fun to buy if you have excess coins, but I wouldn't recommend it.
If you don't mind spending the money, then of course you're going to be in better position at the beginning than those who don't buy it.
I've been free-to-play MUT player for years now.. and I'd say my value/teams is up there with anyone except those who run pack opening streams where people (I have no idea why) give them like money to open packs.
Almost 10M in this last game when getting to 1M was harder than most years.
Here's a list of things I got in MUT 13:
http://www.muthead.com/forums/madden/mut-25-trading/xbox-360/436928-selling-mut-13-stuffMUT 15 I've sold mostly everything except the 4th of July collection, which gives you an 85 overall Jared Allen in MUT 16. (Full collection is worth like 800k though)