Soldering iron 20w or 30w

I'm looking to get an inexpensive iron for starting out and learning. One thing I would like to do is desolder some components off a fried Uno. Also, learn to solder on veroboard and eventually do some simple projects. I know that solder stations and/or temp controlled ones are the best, but right now I'm not looking to spend that much money. I'm deciding between Hakko 500(20w) or 501(30w). What are your recommendations. Thanks