Yeah, I wanted to settle once at level 42 and then at level 69... now I'm targeting level 100. ;)
How much are you gonna spend to buy cards? xD
with 100x10 cards at 5 cents a piece, that's ... 50$ for trading cards haha. How often do you get booster packs? Your Steam level must be insane.
It is a wash or a small profit. I sell most of the expensive* trading cards (except from games I like very much) granted by playing / free booster packs and buy the cheap stuff. I reckon, I get around 30 free booster packs per year.
*if there is an anime girl pictured, chances are good that you can sell them for €0,20 to €1 ;)
With the "Enhanced Steam" browser plugin, you get a quick overview, how expensive it is, to complete a set. And if you have f.e. half of the cards and the completion is over 2 €, you know that you can sell the haldf you already have also for over 2 €... so you don't have to check the price of every single item in your Steam inventory: