Man, you re talking about a $2 card, that is a cantrip. How much more than that could it possibly do (think of Pearl Diver, for example)?? What it basically does, is that it can possibly clear your deck from your "junk". Of course, just one of them won't help, -you 'll probably need 2-3 of them at least to do something, -and you will also probably need an engine to make them work. Additionally, you can make a strategy based on Vagrants. For example, you can combine them with Crossroads for greater drawing power, or you can rely on them to find your ruins for your Death Cart to trash. Additionally, you could buy a few Curses/Ruins when you have trashers that need target (Forager, Trade Route, etc) and find them with the help of your Vagrants.
And other than that, it's always a welcome help for those strategies that want big handsize (Vault, Warehouse, etc) and it can prove to be a great card when there are no filterers on the board...
I like Vagrant, in general. It's cheap and it's what im definitely gonna buy for $2, when i have a +Buy left, or when i'm not sure what i want to buy.